Originally Posted by MightyMaxGS-T

agreed. lol i was just about to say the same thing. the size of your plenum is a huge determining factor as to what tb size to go with. you can't just say one size is good and one size is bad. if i remember correctly if you have a bigger plenum you use a smaller tb and smaller plenum can use bigger tb...i'll go verify that and get back to you. although manifold sizing isn't the only factor, it is a very important one. i will say tho, i have the pro2's with a 66mm tb and s2 manifold and i wish i went bigger. that's why itbs are next on the list...