I've considerd this issue for almost 4 years, what it all comes down to is the
following....do you want a great ride go with the 18" rims, hardly anyone uses
anything else when tracking there cars. (that should be an indication) Plus, the tires are not cheaper if you by quality tires like my Michelins. (not much)
The 19" rims look great depending on which ones you choose but the tires get
in the $300+ range again if you buy quality tires. (each tire Ouch!)
Now considering the 20" or larger the ride suffers (big time) and God help you
if you hit a chuck hole. With 30 series tires you have zero protection for the
rim....Gone If a rim is repairable cost is in the $200 range, some more and others slightly less. Good Luck I currently have two sets 18" & 19"
the 19" are on my G and the 18" are locked away in my garage....

 

I think 20's fill up the wheel opening the best.

 

Love my dubs!

 

20's for sure!

or if you want the donk.....

 

Hard to top that!