downpipe?
 

hey, what do u think the best downpipe is to put on my 05 sti

At least bell mouth with a wastegate separating plate that extends into the turbo housing.

I personally like an entirely separate wastegate pipe that rejoins the main pipe well down the pipe. (AKA Divorced Wastegate)

why?

By merging smoothly down the pipe I'm sure I am not putting back pressure on the back of the turbine. I think there is even a scavenging affect.

With the divorced bell mouth, I'm not convinced it works as well. I think it generates more turbulence rather than smooth flow at /near the turbine exit which can't be that great for flow and generates at last some back pressure on the turbine.

It wold be really nice it the turbo housing flange actually had separate circular exits and not this big nebulous space that we are forced to deal with.

Divorced Wastegate and either ceramic coated (preferred) or heat wrapped to prevent heating the TMIC and engine bay.

Anyone have brands or models they recommend?

Normally, I would have already recommended Crucial, but their new one still hasn't been released.

Stromung... are there any other options :)

Yes.

Personally I recommend bellmouths. Lower failure rate, lower cost, and it's hard to really get them wrong.

cobb. duh. you can't remake one in your garage. aps also uses cast pieces, but theres 3 joints. that's 3 extra places for potential leaks.

I know!!!! It is a prime contender for the replacement of my old BPM if tehy ever get it done...