This thread is so funny. Yeah maybe a larger rim is going to mess with the breaking of a little huyundai with a one pot calliper that belongs on a mountain bike, but larger rims equate to larger tyres which put more rubber on the road.If you've got 225's or larger you don't need to worry about the tyres ballooning under braking. Larger tires also won't balloon as much at high speed, leaving the majority of the tread on the road.If large rims really did decrease performance, they wouldn't put them on cars. There is a limit though, and 18" rim is the max I'd put on my car, and that definitely depends on the type of car it is, because they can be too big. Good luck with the car, it should be a reliable little rig. A friend of mine bought a brand new i20 recently. Nice little run around car, but the seats were like a park bench. She got a 3 year warranty with hers. I personally wouldn't drive one but I'm not interested in fuel economy