Rolf:
I'm thinking the same thing; the F-18 (any of them) with a spin is a handful, and I'm not convinced it's the cat to start on. I like the idea of getting a spin option because we're hearing more about it all the time.
I'd look around for a good used cat in the area (ask someone that REALLY knows what to look for). If you're buying it to race, you'll probably have more fun in traveling to cat regattas instead of trying to find a C scow regatta and traveling 12 hours...
Wyatt