IMHO, the car needs to be lowered. Go with a more aggressive offset. Look for pics of my car and you will see that they don't look small. Less tire helps too.

If you go with 21's, be careful with the offsets you choose with those wheel widths. The lower you go, the more fender work will be needed. If you're keeping similar offsets to what you have now, then you don't have too much too worry about. But if you put 21's without dropping it, it's going to look like a donk.