^ Why not get a turbo back? I mean if he's going to upgrade so much, why bottleneck the build with a cat back? Oh and BTW, a twin scroll turbo is a single turbo unit with two exhaust inlets. This allows the turbo to spool faster. This means he would only need 1 wastegate, this is if the turbo does not have an internal wastegate. Turbo back with 3 inch piping is the way to go.
a turboback means downpipe + catback.. in other words, from the turbo to the end of exhaust - on a standard wrx, stage1 turboback does almost nothing aiya.. sorry, i messed up.. it was really late and i didn't sleep well last night=( .. anyway, it's actually the vf37 that is twin scroll.. so you're right, it's only a BIGGER wastegate.. but if op is in the us, i think to find the vf43 is pretty good already.. coz that turbo comes on the new stock 2.5 motor in the us.. other country don't have more than 2.0.. it's on the 2.5 coz they want to combat the boost creep.. so on a 2.0, it should spool pretty well without boost creep or spikes
do your research on nasioc, there is alot of information on subaru. I went with a VF-34 turbo with sti pink injector, walbro fuel pump, perrin catless down/up pipe, cobb accessport, and a hks exhaust, plus a tune.... put a huge dent in my wallet. All that mod cost as much as my car when I bought it.
yea... but there are more thread that are pointless but interesting on i-club. Nasioc is really good for information, and thats about it.