Anyone running PowerFlex bushings?
 

Hi all.
Just got into the Audi scene with a B7 S4 cabriolet. I love the car, but I noticed a shimmy around 40mph and 60mph. Pulled the front wheels off to find worn out bushings, all 4 uppers. I figure if I'm going to replace the uppers it wouldn't be much more work to replace the lowers at the same time. I've already ordered the PowerFlex Black bushings for all 8, but haven't gotten them yet. My real question is; does anyone out there have experience with these? and if so, what's the ride quality like?
I had poly bushings on my e34, but just the rear lowers and it wasn't a noticeable difference over somewhat worn stock ones.
Thanks.
G