Why get the different manifold what is wrong with just pulling the impellars? I do realize the m90 is going to be a hinderance to a turbo only made to put 400 whp on a mostly stock car, but the t78 can make quite a bit more power top end would the m90 with a stock size pulley be a bad idea just to spool it up?

Thanks for the input. I have never turboed a car I am really new to builds in general.