i will be putting a pi intake on soon so i figured it would be a good time to upgrade the plenum and throttle body. i'm just wondering how difficult it is to port the upper plenum. i have no experience with port work. also how much should i expect to be charged by a shop to do the porting for me. also what would be the best combo, 70mm tb and plenum or 75mm? can the stock plenum be ported to 75mm? would you guys reccommend going with an after markt plenum over porting the stocker?