the T25 is weird... it depends on what car its off of. the T25's on a DSM are way different than a T25 from, say, a Mazdaspeed Protege.. at least as far as the exhaust housing is concerned.

a T25 is too small... its like smaller than a T3 turbo, like the T3 found on an Excort EXP and definitly smaller than the turbo found on the Thunderbirds and SVO mustangs.

a T25 only can push like 13 psi before its all hott air... you cant realy go too fast on a T25. just go and get a normal T3/T4, you can get them used for af ew hundred bucks and they are so common that its no problem to rebuild them.

.89AR on a garrett-based turbo is crazy big for anything smaller than 4.0liters. hell, i wouldnt run more than a .63 AR on my Supra, and thats a freakin 3.0. i dont want anything bigger than a .52 AR on the DSM... our car has like a .43 AR stock, at least, thats what the 6cm mitsu exhaust housing converts to, IIRC.