It doesn't sound like the RE50's are the best bet for tires on the S2000 from what I've been reading here. Unfortunately, most of the recommendations have been for replacing the full set. I was looking at just replacing the rear tires as the front's on my AP2 have a long long life left ahead of them. Did I fail at searching, or can people give recommendations for rear tires to go with the stock front RE50s?

 

Click on Tire Rack banner, search for tires in 245/40-17 and 255/40-17 in the Max Performance category. If price isn't a huge consideration, you might go with RE050A Pole Positions (if you want to keep to same brand). If price is a factor, ContExtremeContact DW, Dunlop Sport Maxx TT, Hankook Ventus V12...

IMO, it's OK to mix/match tires as long as performance characteristics are similar, but there will always be those who will insist on having the same make/model all around.

 

Yes, I would say it's fine to mix and match tires front to rear. Handling and traction characteristics are different front to back (S2000s tend to be tail-happy), so IMO it's not critical that you get identical traction front to back.

However, with that said, I think it's a good idea to have tires in back that are at least as grippy as tires in the front. If not, then you increase the tendency to oversteer, making your car more dangerous when you push it.

I'm personally going with 255/40/17 ContExtremeContact DW as soon as my OEM RE050 rears wear out.

 

Well thats two recommendations for them. They look like a not so aggressive tire pattern, but I'm not very knowledgeable on patterns so that doesn't' mean much to me