[Sjn]

If I understood you correctly, make an array to hold the specific EXP for the levels.

PHP код:

// I am sure you have defined the max turf/level at least. 
new g_TurfLevelEXP[MAX_TURFLEVEL] = { 0, 50, 100, 200, ... }; 


So the level 0 holds 0 EXP, level 1 holds 50, level 2 holds 100 and so on. And you can grab the level EXP by indexing a player's turf ID in this array, I assume it's the GangTurf[x][turfLevel]. I am not quite sure how your turf system works, but I think this will give you an idea at least.