diff --git a/src/app/api/groups/[id]/leaderboard/route.ts b/src/app/api/groups/[id]/leaderboard/route.ts
index 5291fda6..cff63a56 100644
--- a/src/app/api/groups/[id]/leaderboard/route.ts
+++ b/src/app/api/groups/[id]/leaderboard/route.ts
@@ -34,16 +34,23 @@ export async function GET(
     const invoices = await getGroupInvoices(groupId);
 
     // Calculate member stats
-    const memberStats = new Map<string, { owed: bigint; received: bigint }>();
+    const memberStats = new Map<
+      string,
+      { owed: bigint; received: bigint; invoiceCount: number; streak: number }
+    >();
 
     for (const invoice of invoices) {
       for (const recipient of invoice.recipients) {
         if (!memberStats.has(recipient.address)) {
-          memberStats.set(recipient.address, { owed: 0n, received: 0n });
+          memberStats.set(recipient.address, { owed: 0n, received: 0n, invoiceCount: 0, streak: 0 });
         }
 
         const stats = memberStats.get(recipient.address)!;
         stats.owed += recipient.amount;
+        stats.invoiceCount += 1;
+        if (invoice.status === 'paid') {
+          stats.streak += 1;
+        }
 
         // Calculate received amount based on payment ratio
         if (invoice.funded > 0n) {
@@ -71,6 +78,9 @@ export async function GET(
           percentComplete,
           rank: index + 1,
           optedOut,
+          totalPaid: stats.received,
+          invoiceCount: stats.invoiceCount,
+          streak: stats.streak,
         };
       }
     );
diff --git a/src/hooks/useEmailValidation.ts b/src/hooks/useEmailValidation.ts
index 7985f82d..760ad625 100644
--- a/src/hooks/useEmailValidation.ts
+++ b/src/hooks/useEmailValidation.ts
@@ -16,7 +16,15 @@ const EMAIL_PATTERN = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
 const CACHE_TTL = 5 * 60 * 1000; // 5 minutes
 const domainCache = new Map<string, CacheEntry>();
 
-export function useEmailValidation(email: string, debounceMs = 500) {
+export interface UseEmailValidationOptions {
+  debounceMs?: number;
+  checkMx?: boolean;
+}
+
+export function useEmailValidation(
+  email: string,
+  { debounceMs = 500, checkMx = true }: UseEmailValidationOptions = {}
+) {
   const [isValidFormat, setIsValidFormat] = useState(false);
   const [isCheckingMX, setIsCheckingMX] = useState(false);
   const [mxValid, setMxValid] = useState<boolean | null>(null);
@@ -32,7 +40,7 @@ export function useEmailValidation(email: string, debounceMs = 500) {
     const formatValid = EMAIL_PATTERN.test(email);
     setIsValidFormat(formatValid);
 
-    if (!formatValid) {
+    if (!formatValid || !checkMx) {
       setMxValid(null);
       return;
     }
@@ -81,7 +89,7 @@ export function useEmailValidation(email: string, debounceMs = 500) {
         clearTimeout(debounceTimerRef.current);
       }
     };
-  }, [email, debounceMs, checkEmail]);
+  }, [email, debounceMs, checkEmail, checkMx]);
 
   return {
     isValidFormat,
diff --git a/src/hooks/useFilterPresets.ts b/src/hooks/useFilterPresets.ts
index 7894e31c..88dfb2d5 100644
--- a/src/hooks/useFilterPresets.ts
+++ b/src/hooks/useFilterPresets.ts
@@ -36,6 +36,20 @@ export interface UseFilterPresetsResult {
   savePreset: (name: string, filters: Record<string, string>) => string | null;
   renamePreset: (id: string, name: string) => string | null;
   deletePreset: (id: string) => void;
+  exportPresets: () => string;
+  importPresets: (json: string) => void;
+}
+
+function isFilterPreset(value: unknown): value is FilterPreset {
+  if (typeof value !== "object" || value === null) return false;
+  const p = value as Record<string, unknown>;
+  return (
+    typeof p.id === "string" &&
+    typeof p.name === "string" &&
+    typeof p.createdAt === "string" &&
+    typeof p.filters === "object" &&
+    p.filters !== null
+  );
 }
 
 export function useFilterPresets(): UseFilterPresetsResult {
@@ -102,5 +116,32 @@ export function useFilterPresets(): UseFilterPresetsResult {
     [presets]
   );
 
-  return { presets, savePreset, renamePreset, deletePreset };
+  const exportPresets = useCallback((): string => {
+    return JSON.stringify(presets);
+  }, [presets]);
+
+  const importPresets = useCallback(
+    (json: string) => {
+      let parsed: unknown;
+      try {
+        parsed = JSON.parse(json);
+      } catch {
+        throw new Error("Invalid JSON");
+      }
+      if (!Array.isArray(parsed) || !parsed.every(isFilterPreset)) {
+        throw new Error("Invalid preset data");
+      }
+
+      const existingNames = new Set(presets.map((p) => normalizeName(p.name)));
+      const toAdd = parsed.filter((p) => !existingNames.has(normalizeName(p.name)));
+      if (toAdd.length === 0) return;
+
+      const next = [...presets, ...toAdd];
+      setPresets(next);
+      writePresets(next);
+    },
+    [presets]
+  );
+
+  return { presets, savePreset, renamePreset, deletePreset, exportPresets, importPresets };
 }
diff --git a/src/hooks/useGroupLeaderboard.ts b/src/hooks/useGroupLeaderboard.ts
index 20286eb8..7a11e571 100644
--- a/src/hooks/useGroupLeaderboard.ts
+++ b/src/hooks/useGroupLeaderboard.ts
@@ -1,9 +1,9 @@
 'use client';
 
-import { useEffect, useState, useRef } from 'react';
-import type { GroupLeaderboardData } from '@/types/groupLeaderboard';
+import { useEffect, useState, useRef, useMemo } from 'react';
+import type { GroupLeaderboardData, LeaderboardSortBy } from '@/types/groupLeaderboard';
 
-export function useGroupLeaderboard(groupId: string) {
+export function useGroupLeaderboard(groupId: string, sortBy: LeaderboardSortBy = 'totalPaid') {
   const [leaderboard, setLeaderboard] = useState<GroupLeaderboardData | null>(null);
   const [isLoading, setIsLoading] = useState(true);
   const [error, setError] = useState<Error | null>(null);
@@ -49,6 +49,15 @@ export function useGroupLeaderboard(groupId: string) {
 
   const mutate = fetchLeaderboard;
 
+  const sortedLeaderboard = useMemo(() => {
+    if (!leaderboard) return leaderboard;
+    const members = [...leaderboard.members].sort((a, b) => {
+      const diff = Number(b[sortBy]) - Number(a[sortBy]);
+      return diff !== 0 ? diff : a.rank - b.rank;
+    });
+    return { ...leaderboard, members };
+  }, [leaderboard, sortBy]);
+
   useEffect(() => {
     mountedRef.current = true;
 
@@ -71,7 +80,7 @@ export function useGroupLeaderboard(groupId: string) {
   }, [groupId]);
 
   return {
-    leaderboard,
+    leaderboard: sortedLeaderboard,
     isLoading,
     error,
     updateOptOut,
diff --git a/src/hooks/useSplitCalculator.ts b/src/hooks/useSplitCalculator.ts
index ba0f5efa..46046c81 100644
--- a/src/hooks/useSplitCalculator.ts
+++ b/src/hooks/useSplitCalculator.ts
@@ -54,8 +54,12 @@ export interface RoundingResolution {
 
 const STROOP_SCALE = 1e7;
 
-function roundToStroops(value: number): number {
-  return Math.round(value * STROOP_SCALE) / STROOP_SCALE;
+export type RoundingMode = 'floor' | 'ceil' | 'nearest';
+
+function roundToStroops(value: number, mode: RoundingMode = 'nearest'): number {
+  const scaled = value * STROOP_SCALE;
+  const rounded = mode === 'floor' ? Math.floor(scaled) : mode === 'ceil' ? Math.ceil(scaled) : Math.round(scaled);
+  return rounded / STROOP_SCALE;
 }
 
 export function validateShares(recipients: RecipientLine[]): SplitValidation {
@@ -103,13 +107,27 @@ export function validateShares(recipients: RecipientLine[]): SplitValidation {
 export function calculateSplit(
   totalAmount: number,
   recipients: RecipientLine[],
-  _assetCode: 'XLM' | 'USDC' = 'USDC'
+  _assetCode: 'XLM' | 'USDC' = 'USDC',
+  roundingMode: RoundingMode = 'nearest'
 ): SplitCalculatorResult {
   const totalNum = totalAmount || 0;
   const validation = validateShares(recipients);
 
-  const derivedLines: DerivedRecipientLine[] = recipients.map((r) => {
-    const grossAmount = roundToStroops((totalNum * (r.sharePercent || 0)) / 100);
+  const grossAmounts = recipients.map((r) =>
+    roundToStroops((totalNum * (r.sharePercent || 0)) / 100, roundingMode)
+  );
+
+  if (recipients.length > 0) {
+    const totalStroops = Math.round(totalNum * STROOP_SCALE);
+    const sumStroops = grossAmounts.reduce((s, v) => s + Math.round(v * STROOP_SCALE), 0);
+    const remainderStroops = totalStroops - sumStroops;
+    if (remainderStroops !== 0) {
+      grossAmounts[0] = (Math.round(grossAmounts[0] * STROOP_SCALE) + remainderStroops) / STROOP_SCALE;
+    }
+  }
+
+  const derivedLines: DerivedRecipientLine[] = recipients.map((r, i) => {
+    const grossAmount = grossAmounts[i];
     const preFeeAmount = grossAmount;
     const effectiveTaxAmount = roundToStroops(
       (preFeeAmount * (r.taxRatePercent || 0)) / 100
@@ -153,11 +171,12 @@ export function calculateSplit(
 export function useSplitCalculator(
   totalAmount: number,
   recipients: RecipientLine[],
-  assetCode: 'XLM' | 'USDC' = 'USDC'
+  assetCode: 'XLM' | 'USDC' = 'USDC',
+  roundingMode: RoundingMode = 'nearest'
 ): SplitCalculatorResult {
   return useMemo(
-    () => calculateSplit(totalAmount, recipients, assetCode),
-    [totalAmount, recipients, assetCode]
+    () => calculateSplit(totalAmount, recipients, assetCode, roundingMode),
+    [totalAmount, recipients, assetCode, roundingMode]
   );
 }
 
diff --git a/src/types/groupLeaderboard.ts b/src/types/groupLeaderboard.ts
index 52256ab6..aae5fb35 100644
--- a/src/types/groupLeaderboard.ts
+++ b/src/types/groupLeaderboard.ts
@@ -6,8 +6,13 @@ export interface GroupMember {
   percentComplete: number;
   rank: number;
   optedOut: boolean;
+  totalPaid: bigint;
+  invoiceCount: number;
+  streak: number;
 }
 
+export type LeaderboardSortBy = 'totalPaid' | 'invoiceCount' | 'streak';
+
 export interface GroupLeaderboardData {
   groupId: string;
   members: GroupMember[];