uuummm 8cm clearence is illegal dude... it has to be 10cm. If the guy who does your exhaust is any good he'll be able to tuck it up so the car could be legal... dunnow how low your kit is though... and you wouldn't need boddy work for 18s providing the offset is greater than +43 but you would need an engerneers since the largest size rim releaced in the EGs was the SiR which had 15s stock which means the biggest you can go is 17s.