tirerack.com lists a regular and a RunFlat version of the 17" Dunlop Winter Sport M3 tire that fit the Rx-8. Has anyone tried the RunFlat?

 

I asked Connor from TireRack this same question and here's what he told me:

I would say no on the premise that the run flats will be much stiffer and this will take away from the ice and snow traction. They are also more expensive. the benefit of the run flat is the added security that if you ever get a flat you will have the ability to keep driving and not be stranded. Seeing as you are keeping the TPMS system in tact you will be able see when you are getting a low tire and hopefully head in a direction to have it checked out. if you are in a situation where the tire just blows out from some form of impact then you would be stranded with the non run flat tire. There are benefits both ways, but the final decision would be up to you.

I personally ended up not getting the RunFlats since I was getting the TPMS installed. Actually the tires were supposed to show up on Friday but the UPS guy forgot so I have to wait till Monday now.