I have seen many post regarding the ride going from 15" wheels to 17" wheels...and thought that I'd add my 2cents.
Monday I removed the stock 15" "bottle cap" wheels with 60 series tires and put on my newly aquired 17" "Throwing stars" with 45 series tires...and in this instance Pirelli P210 snow tires.
I have yet to come up with a negative...well cost maybe. The change to the look of the car is dramatic! Looks like a totally different car. +1. The change to the handling is also dramatic! The improvement reminded me of the difference between driving a truck and driving a car...the increased reaction and feedback at the steering wheel is a nice change. +2
Let's see, here's a minor negative...the reduced side wall flex highlights body roll. It doesn't make it any worse...just makes you notice it more. I think that the stock spring/shock combination is balanced with the 15" tire side wall flex...so, it's alittle more "natural".
So, doing the +2 wheel change does seem to make you want to do the spring/shock change as well. But for now, I think I'll be plenty happy with the improved looks and handling.
92 525im - w/M5"ThrowingStars"
P.S. For the ever present question about increased harshness...I have driven 700 miles since the change, and the only harshness is potholes and speedbumps. Basically the things that had made you grit your teeth with 15"ers, now rattles them. I would -definately- do this "upgrade" again. For that matter, I'm looking forward to the 150miles on Monday, and the 500miles on Tuesday!