Go with RCC for sure. A stock engined stage 1 gen 1 will be good for mid to upper 200's in hp. If tuned correctly you'll never notice the turbo until you want to. Keep it low boost and you can run pump gas. If you have a gen 1 you may want to get a second fan if you plan to commute in traffic. It's an easy mod and you can find info on this site about the install. If you get a used kit you'll shoot yourself in the foot. If you get a kit from a sketchy or unproven seller you'll be taking a major chance. I bought a used bike in pieces with a very used Mr.Turbo kit and ended up spending a fortune in time and money only to end up with an entirely new kit bought almost one piece at a time.
The gen 1's return line can be a ***** to get routed such that it doesn't kink, but done correctly it will be fine forever (you can get help on-line with that too). If you go with RCC your stage 1 kit comes with fool proof instructions with pictures and their stage 1 kit is upgradeable to 420hp with additional injectors. If you want to get into the 300+ hp range you'd want to run a spacer plate, rods, and clutch springs. When you get your kit installed take it to a good tuner. Ask the tuner how they set up turbo bikes as opposed to n/a bikes. If they say there's no difference then find a different tuner. I'm constantly surprised with how many "good" tuners won't admit they don't know turbos. There are threads on turbo dyno'ing and I know from recent and personal experience that Richard (RCC) will help your tuner on the phone so no melting will occur. There is NO REASON a bike should melt on the dyno, so don't freak out about the hype.
You can also run a wide band a/f monitor (power commander/wego/etc) which will allow you to monitor and log you a/f. Some people tune with these but I've never been able to imagine full throttle pulls on public roads(yikes). If you chose to run a wide band they'll cost you about 300.00 and you'll want to decide before you order your kit as they need an O2 bung welded n the dump pipe.
Your stock chain and clutch will be ok with 250'ish' hp. 250 hp will be very exciting, for awhile, then you'll want 300, which will be exciting for awhile, then you'll want 350, which will be exciting for awhile...etc.
I stopped at 300 (my last bike) and I can tell you that full throttle in third at 70mph meant tire that before you could even let off the throttle the back wheel would spin AND the bike would wheely at the same. Don't be fooled by claims of Nitrous, it's just not the same. Good luck.
