I have 18's on mine, from what I've heard, 20's could cause a rubbing problem under your fenders. The fix would be to roll the fender edges to allow clearance for the wheels.
Whats up man I got 20's on my s500 I have seen hundreds of s40 with 20's also I have a set for sell with tires for 1500... 20X8.5 front with 245/35/20 and rear 20X10 with 275/30/20 picture on my post below hit me back at codqs674@yahoo.com if you want them
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