See i'm not that much of a connoisseur to be honest. If i've not driven either, the Gen 1 will be immense compared to what im driving now. Its the reliability and Porsche anxiety which terrifies me.
Another reason to get a gen2
It's not about connoisseuring, it's about the fact the gen1 suspension really is quite duff and the sport mode unsusable on UK roads, plus the satnav doesn't even have 7 digit postcodes on the early cars! It's like going from a 300ZX to a 350Z, such is the difference. A 987 Cayman R would have to be in with a shout at that budget level though, arguably more special?
Tbh anything you've mentioned on here carries a risk cost, be it Pork or Maser or R8 or old Mustang: All have their own expensive parts. Hell, so does a 350 now the engine replacement costs have jumped. That said, there's nothing here likely to cost anything more than a 3 series, which you've been happy to own and certainly nothing compares to repair costs on an RRS! Do your research and you'll stop being so worried, as I've said before a proper inspection on a 997.1 removes 95% of the risk of something catching you out, and part costs are the same or cheaper than a 350.
MaserGT is an amazing car, but I'd want the 4.7 with the robotised manual, not the auto. If you love the Merc then the finance deals on them are pretty attractive right now, go drive one and see if you can justify it. You're only here once