well if you can afford it, e85 aka going flex fuel, will benefit significantly even with just a stock turbo. the turbos i listed off would all most likely be in the upper 300s at the tires, maybe the low 400s on pump gas.
as far as rotated, yes you can run a rotated setup with a top mount intercooler. although you may have to have a custom y pipe adapter made to work with a tmic. i do believe IAG can make a kit designed to work with tmic, and i think map performance does as well. some rotated kits will not be compatible with a top mount, some will, some will require the custom y pipe for tmic, jsut have to research which one will work and which wont. the benefit of going rotated even on a relatively smaller turbo is the turbo's exhaust housing or hotside, the oem type housing found on stock turbos and stock location turbos is very restrictive, so when you go rotated, you will get a better hotside that will allow the turbo to breathe better, resulting in faster spool up and more power up top vs a stock location turbo of the same size. I went stock location and wish i'd have just spent the extra money to go rotated. but turbo tech has come a long way, and turbos even in a stock location can perform extremely well and be alot of fun. the dom 1.5xtr probably wont break 400 on pump gas, but it will come very close. when you start trying for stock location turbos to hit 450, they tend to get very laggy because of how big they need to be, my old roomate had an fp red or black (cant remember which) on his 05 sti, and i had a 20g on my 06. his did make 423whp on pump gas, while mine, at the time, was only making 346whp, even though mine was making less, both of us agreed mine was much more fun on the street even though his was faster, just because of how fast it came on. basically i'm trying to say, if you are only going to run pump gas and a stock location turbo, i'd stay with the 1.5xtr even though it likely wont make 400, upper 300s is plenty fun, and if i remember correctly, we'd consistently see 385-390whp on sti's with the 1.5 on pump gas when i was at mach v motorsports. (the dyno was average reading dynojet, stock sti would put in the 240whp range)
