Jon,
I know what you mean about the old original MPSC. That was a pretty good tire and wore REALLY well. Never got to use it in the rain though.
Incidentally i've been keeping my eye on the Trofeo R because I think i'll end up using these on my '86 for the occasional DE day. I'm hoping they're a good all around tire. Good size selection so far and nice pricing So if you go with these tires, do let us know what your experience finds.
Speaking of rain capability, the RA-1 is a solid rain tire. I used those for a few years on my racecar as my rains. Don't get me wrong, they can't hold a candle to Hoosier rains (especially the H20 which is ungodly good) but they were OK enough to keep me going straight ahead and not crap my pants. Here's a video from Putnam Park in the rain, which is a pretty slippery track in the wet. I get around OK but certainly nothing to boast about. Just showing what the car behaves like. You definitely can't keep trying to run the "dry line" @ Putnam in the rain if you don't have H20s!
https://vimeo.com/24037303
I recall doing a DE event with the racecar and the first session or two of the day was a massive downpour. Ran the whole session & at the end, only me and my buddy Stefan were still out there. Everybody else parked it, so it must have been coming down pretty hard. I recall feeling kinda bad for head safety guy flagging the start/finish line . I think he may have hunted down Stefan and gave him some grief for us staying out the whole time.
I paid for the day, might as well get me money's worth out of it? Later in the day a guy asks if I had rain tires. Nah, just Toyo RA-1 since they're fairly OK at full tread. He was kinda surprised.
I feel your pain/difficulty in analyzing this. It's tough to find a happy medium that suits your needs for a street driven track car. Eventually if you get really hooked on it, you might end up with a dedicated set of track wheels & tires like most people do. I'm not saying driving to/from the track on your R comp tires can't be done. Lots of people do it. I've done it too.
Just saying that i've found on a number of occasions that the tires get to a point where you're in a dicey position if it rains. Because, 1.) Your track day ends up sucking butt if it rains most of the day and you're stuck with your skittish dry tires, possibly forcing you to sit out most of the day 2.) the ride to/from the track can be a bit dangerous. I once got caught in a strong long duration rain storm on the ride home from the track. I had to pull over and wait out the heavy stuff because I could feel the car was hydroplaning. Even when the rain let up a bit, I could still feel it planing and I was limited to 50 mph on the highway. Any faster than that and it was on the verge of control. Weird feeling of the car "floating" as you're driving straight down the highway! I promised myself I wasn't going to do that again.
Hauling your tires around is pretty easy if you take out the passenger seat. I was able to put all four in the passenger area sitting upright in a line. 16x8/9 with 225/245 tires. I tied them to the passenger door pull and also to the harness bar that spanned the window pillars, along with bracing them against a heavy toolbox sitting on the floor