Both the exhaust and DP are being custom built by a local performance shop called IPS Motorsports (http://www.ipsmotorsports.net). I had my car at their shop yesterday for final measurements and to test fit a custom part they had machined for the DP. BeerEngineer actually introduced me to them via a dyno day we did back in March (thanks Zak).
They are big in GM tuning (had 3 customer Z06s in front of their shop when I was there) but also do a lot of work on 3000GTs, SRT4's (and other MOPAR products) as well as Evos, STIs, G35s, Audis, etc. Follow the link above or search youtube and you'll find their world record setting 1/4 mile Vette. I've seen both the orange and yellow vette's in person...wicked is all I can say.
After DP and exhaust, we're going to talk about doing a FMIC and CAI and maybe a custom tune once they've had more time to research and tinker with the R. If all goes well, they plan to use my car to develop production worthy parts to market to other R owners. I'll post more on this in a separate post once we're further down the path.
Another supplier of performance parts for the R there soon may be. http://********************/smile/emthup.gif