You can put up to 20's on your ride if you can find them. The trick is getting a 20 x 7.5 with a +35mm offset (most common). You can also fit a 20 x 8 if you can get it with a +45mm offset. 19's are the same except that they are a little more expensive that 20s believe it or not because of their rareity. If you wanna go with the staggered look or put M3 wheels, you have to be prepared because the back wheels will stick out about 1/2" You will probably need to roll your fenders, add a coil over spring shocks, and go with no more than a 265 wide tire. Or you can just do what I did and spend 10 bucks on spring spacers and add the wider wheel in the back.
And there is nothing wrong with chrome wheels. I got chrome 19" hamman's pg-2 style wheels 19 x 8.5 in front with 225/40/19 in front and 19 x 9.5 with 265/30/19 in the rear and looks pimpin especially with the topaz blue paint.