4.5k rpm and 110mph? You'll barely have to slow down the slow chicane, and you might as well sleep on the fast stuff...
Yes, a single seater is a magical experience, but at such lame speeds it won't be that interesting. The Cayman might be okay, but it'll also be limited somehow I guess. You're much more likely to get comfortable (and comfortable = quicker = more fun [up to a point]) in the MX-5 for 15 laps.
Could be that Kev. I don't know. I don't even think about what might happen if something failed at 150mph. This year I do have a lot more confidence in the car and in my ability to tame it - that might come across as arrogance, but I like to think it's a self-belief that I've been missing thus far.