hey guys does any one know the rules on tyres and rims at motorvation for example if you have 20 inch rims do you have to have 20's on front and rear or can you run your 20's on the front and whatever you want on the rear , because im going to start buying tyres now and i want to know if i have to buy 20's or if i can run pursuits and buy some 15's ? can anyone help???