Jay is correct, as far as finding a competent mechanic on Guam. You'd have to take it to the dealer if you want it done right. Even at that, they're probably still not the best qualified, experienced, or knowledgeable mechanics.
I have however seen the trend change a lot in the past couple of years in that most dealers are really making sure that their mechanics are up to par in the latest technologies and training available.
As far as other exotics to race, I'd say zero! Sure there's a Testarossa, 308, couple of Porsches, 1 viper, couple of vettes, and some prowlers, but the hard part is meeting up with them when both of you are driving your cars, and finding space to race in the stop and go traffic. There's no legal drap strip out here(it's being built right now), and from one traffic light to the next it's real close that there's not enough room to really open up.
All is not lost though, as one can find happiness just driving the car. By the end of February we should have our 1/4 mile strip ready for racing, and that's something I've been looking forward to for a couple of years now
Jay, the 348 was shipped off island, at least that's what I heard. I don't see it anymore.