I've owned two RX7s in the past, and I'll be the first one to say it is not a boxster. It never left me with a permagrin even though it was fun to drive. When my last one was broken in to and they stole my 5K stereo system, rather than sink any more money in to it I gave it away to my brother in law. Never missed it. I can't say that would be true of the boxster.
The bottom line though is get what you want, just make sure it is as enjoyable as what you are giving up.
