I've got 16s and personally i think thats the perfect size, everyone usualu goes for 15s , if i had 15s my exhaust would touch the floor! ahh corolla ?! was it hard to make fit? my mate owns a bodyshop so could get it done propperly,I've just payed 40 pounds for a laguna splitter lol so will use that for now really nice car mate keep up the good work