[asshanson]

If it's only a weekend warrior/track car, have you considered a street-track compromise tire? Maybe not an issue if you're getting used freebies from your brother, but the new Toyo R888R looks to be pretty good and available in the 255/35/18 size you'd need (and definitely stickier than the RE71R but with probably half the tread life). I agree with your brother don't go bigger than 255 on a dual purpose car. Rolling fenders, tires sticking out, harder to turn, etc. Don't make it a full out race car with tires as wide as a barn.

Rain is not that big of a deal if you are smart about it. I've been in really heavy downpours in my NT01 which are virtually slicks, and I just stayed under 40mph and made it home fine. Not ideal of course for a daily driver, but you said no plans to drive in rain, so emergency only and you'll be fine.

Or go with the R7 if you can change wheels at the track haha. A7 would probably heat up way too quick with a heavy DSM, unless you were doing only a couple laps at a time.

Sounds like it's coming together nicely, much progress made. I wish I had as much time to work on mine, it just sits there collecting dust most of the time.