SL55 wheels - is 20" too big?

[Blu3R]

I'm not a huge fan of the turbine wheels on the SL55 and as I'm looking at replacing tyres now I'm considering the idea of replacing the wheel with something bigger. 19s seem the logical move but having seen a lot of pictures (mostly from the US) of cars with 20s it's got me thinking - would they be horrible on our roads? The difference in cost isn't prohibitive so really it'll all be down to the ride quality and their resilience to being BMW brittle.

Can anyone offer their thoughts?

[KAAMG]

I deliberated over this for quite some time on an SL55 (again moving up from the 18" Turbines). I finally opted for the genuine 19" AMG split rims, and was very happy with my choice. The ride was noticeably harder on the 19's, so would imagine this may be a slight issue with 20's if that's a concern. The other thing which ultimately swayed me was 1) staying original AMG, and 2) most of the images of 20's I saw had also had the SL lowered in some fashion (lowering module/links etc) to close the gap between the wheel and arch. In my opinion this would be a requirement cosmetically, otherwise the 20's just look odd. This adds further cost, and again probably impacts on ride quality. Just my thoughts from the time - hth!