That pizza dude writes:

<<So, do I get the additional handling/performance of the R1 on the street, or do I bite the $1300 bullet and buy the MXX3? The R1s would be about $700, mounted, balanced, installed, and aligned. (The MXX3 price includes all that, too.) Is anyone out there a nut like me who would use R1 on the street? If so, please give me your impressions for everyday use. Any advice?>>

If you take it easy on full tread R1's, you might get over 2000 miles out of them before wet driving safety becomes a *major* issue. Problem is, the grip is so good you'll use it at every opportunity (trust me on this one :-)), which means tire life will suffer. You might consider Toyo Proxes or Yoko A032R's instead. You'd be more cost effective buying the street tires any way you look at it. FWIW, I'm running BS retreads(!) on the street (I just want cheap, long wearing, deep tread tires there) and using the saving to keep an inventory of race tires for the their intended purpose. My street racing days are history. I'm too conscious of the potential consequences at my old age! I couldn't live with the guilt of taking an innocent, loved-one's life. The grip level on the R1's is so high that if you get in over your head, it'll mean serious trouble on the street.

<<Also, I know I've asked before, but I still haven't gotten a definitive answer, yet: Will 235/45 front and 255/40 rear clear the fenders? And, if so, will they upset the ASC-T system?>>

They should just clear, unless the car is lowered, then you *might* have a problem in the rear. At the stock height, if they do rub (for some reason the right rear lip is more susceptable than the left, E36 M3), it will be very minor and of no concern.