Anyone running oversized tires on 16" wheels on their A4? I'm thinking about stepping up to a 215/55/16...

 

If you want to upsize your tires for a wider contact patch, make sure to take into account the fact that when you widen without reducing your sidewall height, you will throw off speedo and odometer calibrations (and maybe other things as well). Use this link to help you in your tire sizing (it'll help you pick a tire size that is as close to stock rolling circumference as possible):

http://www.miata.net/garage/tirecalc.html

Type in your OEM tire size and the size you're considering, and then see what kind of difference it makes, and then play with the numbers until you find something that is as little compromise as possible.