I just had my Tri Ovals done yesterday with my 500 mile service as well. Chrome/Chrome for me, since I have the AG version with all chrome accents. Looks fantastic, and sounds even better.
I'm very happy with my dealer (long time customer with them), and I received some amazing express service on this occasion as well. I called them Monday morning this week to set up a time to get the bike in, then dropped off the bike on Monday night, and it was ready for me at Noon on Tuesday (next day). They even fixed my initial bugs, including drive belt and shift linkage adjustments. It rides perfect now.
Regarding power increase, I honestly think it is just the fact that it sounds so much better, that it makes you feel like its got more power, but I would doubt that in reality it would add more than an HP or two. No matter, it is so much more enjoyable to ride now, and that is the main thing.
I came from a totally custom chopper with over $10k in motor work. Yes it was a torque beast, and a blast to simply try to hang on to as you twisted the throttle, but it really wore the hell out you after an hour or two of constant strain. In comparison, this XC with the Tri Oval addition is now as enjoyable to get on and ride as my chopper was, with the big plus being that I don't get tired of hanging on after an hour or two, and can ride this one all day long without even thinking about having to take a break. Awesome.