E-Revo/SUMMIT Foam Pad Chassis - difference?

Found this 5622X http://www.wheelspinmodels.co.uk/products/5622X.jpg
and the stock grey 5622 http://www.traxxas.dk/images/TRX5622.jpg

But what is the diffrence between these two?
Only diffrence i can find is that the X is almost black, but the X is cheaper?!

IMO the "X" is the coolest foam pad, so if the only diffence is the color and price i go for the X