all you can do mate is read other peoples posts, me and daz have got the same mods, apart from me having a 2.5" cat back, and we are both over 175bhp, i reckon having the 19's on robbed me of 1 or 2bhp.lol
Then work out future mods, cams = proven 10bhp, 4-1 = 3-4bhp, remap - at least 10bhp, more likely 13bhp.