Meh who cares, if it happens it happens, modified vehicles esp exhaust keep it legal limit your alright, there will be no real defect then, keep you cat converter your alright, box your pod you'll be ok why wouldnt you box it anyway CAI is better by far anyway, easy enough to solid mount it as well, out of site out of mind I say, that hieght restriction been around for ever really, just keep it at legal limit, FFS if your really worried get a mod plate or eng cert on certain mods, and the easiest of them all is just dont be ffing stupid on the roads. Keep safe and you will be ok.
All this worry about these laws i mean wtf, its not that hard to make certain things legal on your car is it? and still not hinder on performance. All i can say is that EVEN if you did riot what reason have you got to riot, its mainly dickheads in the past that have caused them to mainly come into place ie: (Street drags, racing and the like around the public eye) not on the area it should be at the track/strip. They'll just laugh at you if you riot just throw a little more fuel on the fire. The papers and news would love it.
Worry when it does happen, at the moment its just talk.
cheers
A