NO 20s!!!!! (unles you like major car problems and being ridiculed! no offence)
I'm doing 16s and they are very perfect.
The biggest I would go is 17", 18" at the most!!
Use this to view wheels and sizes on your car. There are a few 20s in there, and you can't even see the tire!
Upgrade Garage - Wheel Search - White 2001 Honda Civic EX Sedan