Ok... so I bought the 18" M6 reps (from **********s.com) with a set of PS2s... oh and a BMW mobility kit.
First, I would like to say that the wheels look great and the **********s.com guys were super-cool answering all my lame questions.
Second, the difference between the RFTs vs. Non-RFTs is significant.
The ride is much more civilized... no more tramlining and the grip on these tires is unreal.
Definitely worth doing.
-Dan