Not a lot matey. Mostly it seems to be personal preference. There is a slight gain in extra BHP apparently with that trophy going to the K&N. I also believe the Green doesnt come with any cold air feed pipes like the K&N but a fair amount of people havent fitted the cold air feed pipes with the K&N anyway. The K&N seems to fit better aswell. In terms of how they look for me it would be Green every time. I dont have an ST though so im only passing on what I've read.