For me, the RA1 is a great dual purpose tire. Feel free to use it on track or off. Perhaps just drive a bit slower in the rain
They are being phased out in favor of their new R888 tire. See their website
www.toyo.com
1) You don't mention what sizes you currently use.. 205/255?
If so, I would try a 225/255 or 225/245 combo to help dial out understeer. Ihad 18"s on mine and ran a 225/275 combo. I think the 275s were too much. Either needed 245s on the front (which wouldn't fit) or 245s on the rear. Then again, I like a car that can be made to oversteer easily.
2) If you like wasting an hour or so changing tires at tn event (mmm lots of fun on hot afternoons
) you might get a small tire trailer. I have seen many over the years. They likely cost $500-800. Can tote 4 wheels and a small box (for tools, jack etc). Check out som autocross forums as they are, i think, more popular with that crowd than the track crowd.