[ronster]

Sportech, in Campbell, CA, does this and they sound very good without the drone usually associated with the "sport" mufflers and no emission problems. They remove about 65% of the baffles. On a 986 Boxster they charge $695 for a swap out. They claim, when done with headers (they use Chinese eBay headers of which they've been running for two years with no incident) an 11 hp increase. The headers and header installation runs the cost to around $1K.