I have a 04 S2K I see skunk2 offers a billet TB this should help the bottom end for a little more grunt most say. I see they have three sizes listed 66mm, 68mm and 70mm which is best for my N/A S2000 with an i/h/tp/e ?

What kind of gains should I expect for the 260ish price tag?

 

I'd go with the largest. be sure to check your intake manifold, there is a chance you need to port match it then!

 

i think the skunk2 is only larger on one side but im not 100% on that.