Yes the piping is polished on the Turbo XS. I doubt they will fit GC8 without some modification. The Injen unit allows use of stock BOV. The Turbo XS is designed only for their Bypass valve. We can of course weld a flange on the piping for whatever BOV you wish to use. Price to Hawaii is $1025 shipped Fed Ex 2 day air. I usually see gains of about 30-35 whp with a FMIC on a WRX with upgraded turbo. If you have a REALLY big turbo, even more so.