Here is a quick review, I apologize for not being a professional reviewer but I'd thought I'd share my experience with them!

Yokohoma S.Drives
245/40/18 all around
stock wheels,
stock suspension

For those of you that like a quiet smooth ride, you will love the S.Drives, they are extremely quiet and the ride feels like you are on soft sponges!!! I never knew the rx8 will become an even smoother ride.... I don't do much track racing but these tires don't have a problem riding up the canyons wavy roads... I highly recommend these tires to anyone looking for a summer performance... I have not tried them on snow yet, but they do just fine in wet conditions .. haha I got my winter beater for snow driving.
here are some pictures:

 

nice looking tires and 8

--Jonathan

 

Sweet. I was thinking of getting those tires next spring.

Good to know they're worked out well on an other rx8