So all in all to sum up my question. In case someone is looking in to it. 5/16" is the way to go. 1/2" is for highr rpm's. and the TB is a worthless mod. Thanks guys.

 

^Exactly.

 

Simple physics...if you don't have (or are not planning in the near future going with FI), go with the 5/16. It is the computers curve that makes the difference. Its like a long balloon. Grip one side...the other gets bigger but you loose on the ladder side. Get a 1/2 spacer...you gain more on the high range. Get a tune...still gripping on the balloon somewhere. Something will give. More air volume in the plenum will not be efficient in all ranges until ALL of the aspirated system is upgraded to scale. So in other words...when you get from the mod in mid range....you take from high range (yes even with a tune...that just distributes it a bit better). If you are not at the track often...and don't plan on FI in the near future...go with the 5/16 ISO. I can personally say, I do notice a BIT on the mid range...which is what I wanted for my situation with the 5/16.

 

simple daily driver here with 5/16 spacer for the usable mid-range power increase (area underneath the curve..).