hey i just got a new giant vt3 frame from wheel world for $399! i need a little help though. it came with a seatpost shim (30.8-27.2) should i just buy a 27.2 post or try and find an oddball 30.8, will using the shim be a weak link on my bike? what size front derailler to i use? i want to use 8 spd. xt or xtr, i know its bottom pull. i'll be using a fox vanilla 125 rlc and hayes 8" hydros. if youve got experience with this bike and can give me any advice i thanks you in advance-brian