I just recently bought and chipped a 2005.5 A4. I am looking to take the next step with a set of summer wheels and tires. What size can I go to? 19"? 20"? How do I upgrade and still have the option of putting the factory wheels and rims back on for the wonderful Jersey winters?

 

You could 20's if you like, but i wouldn't do more then 19's.

 

I'm totally new to the Audi world, so take my comment with a grain of salt. But tires are tires...

The first question is how long have you been driving?
Do you have any track time?
Are you going for looks, safety or handling? (Big rims are looks, and more often than not, sacrifice safety and handling)

I never recommend low profile tires to a relatively new driver. The firm sidewalls and limited slip angle provide no waring to its adhesion limits. A standard tire offers more feedback to a driver, and alerts you to its limits before sliding.

Recommend you research the following terms and understand their effects on handling before you purchase big rims, just so you know what your gaining and loosing.
"Slip Angle" and "Unsprung weight"

peace
Vince

 

There's lots of people running 19s, a few running 20s. It also depends if you're planning to lower your car at all, how much you want it lower and how much wheel clearance you want so you won't rub.