George,

Before I get started; I'm not against the change, I'm actually for it. I think it might be an opportunity. And I'm not trying to start another heated argument, just trying to raise some issues.

But...

I'm not so sure about the "no performance advantage". If you go to Hoosier's website and look at the specs on the tires available between 15 and 14. The difference in circumference (ie travel distance) varies from no difference to a 6" difference. Thats enough for a 7 mph difference (on paper) without changing any gear ratios. (3.90:1 diff @ 5500rpm, 71.5: vs 77.1") And the track varies from no difference to a 2" increase. Theres alot to play around with there. And alot of potential dollars spent on comparing the two. ($700 a set for panasports and I already have 3 sets)
Making the change would also cost alot more than the RR shock setup for my car that some of us had to just toss in the basement.

Have y'all looked into the development costs with a change like this? Or is it just, "if you don't want to change, don't". A lot of people without RR shocks didn't like being told that when confronted with that new cost.
How is this any different?

For me, I'd wait and see before I change. I have too many sets of tires and wheels. But as the sets dwindle, I'll spend the money to test with 15's because it may make some difference. And that one test session is going to cost $700 tires + $700 wheels + $150 for a test day. And if it works, add another $3000 on top of that for spares and a set of rains just to stay competitive.

This "little","no advantage" change has the potential of costing about $5000.

Those RR shocks were just $2700 for my car.

Tom