Yes, you should get the PS AS 4"s if the MXM4's don't do it for you. The AS 4's are a big jump up in performance and a substantial hit in efficiency. I've got 50,000 miles or so on MXM4's on our two 3's on 18" wheels. i've got 3500 miles on the AS 4's on one of the cars. There is just no comparison in handling and braking. I can easily feel the difference just driving around town. The PS 4's are way better than the MSM4's on dry pavement. I haven't yet had a chance to use them in other conditions but they could hardly be worse in the wet and reports are that they are a lot better.
The efficiency hit is in the range of 10 to 13% at 77 mph.
Excellent feedback!
