Well I am glad to see there is a little interest in this set up.
I have a compressor housing here off of a Legacy. This is what I see potential wise for a 100% bolt up application. About as far as you are going to go with it being efficient is a 20G compressor wheel. Anything beyond 42-43 lb/min is going to be inefficient in the compressor housing. There is just not enough diffuser length to make say a 50 trim or other wheels similar to it work effectively with a big back disc (exducer dimension). I am looking for a 100% bolt up, no fabrication required set up that is user friendly. I don't want to break records or strive for the most power anyone has ever made with the turbo. My 3 main charactoristics for my builds are quality, reliability, and good power potential. If it doesn't have any of the 3, I will not build it.
My idea for you guys is a bolt up EVO3 16g for the guys that want response and a great streetable turbocharger. This is my absolute favorite turbo on my 1.8L 1988 Mazda 323 GTX. I run 22 psi on it daily and its an absolute blast to drive on the street. I am sure this would be one of your favorites as well
. I ran a 7cm2 TD06H and a 50 trim for about a year. The only thing about that turbo was I really had to be bad on the car to go anywhere in 1st gear. And also if I wasn't speed shifting the boost would fall off between shifts and the car would take a few fractions of a second to get that turbo up to speed again. Just wasn't near as fun as the evo3. The evo 3 is there when you hit the gas and makes great TQ through the band.
Also the 18G is a good choice and also the 20G. So let me know some input from you guys and I would be happy to listen!