if the car was tuned with a 50 trim turbo and then swapped out for different A/R turbine housings only what RPM would the car start to show boost for each different A/R. of course tuned properly for each A/R. all T3 turbine housings. .48 a/r vs .63 a/r vs .82 a/r (also note the center housing is bored for a stg1 wheel vs the stg3 wheels on the other housings) http://i71.photobucket.com/albums/i123/mattgroshong/t360trimandhousingpics018.jpg