Personally, I wouldn't go with 20's for a number of reasons. Regarding wheel manufacturers, I recommend VMR's if you can get them. They offer of number of styles and finishes in Square or staggered fitments. They have an impressive gallery on their website, although it seems to be offline right now. Tell them what you're looking for and they'll get you dialed in.
http://velocitymotoring.com/wheels.html