Looks to me like the law is directed at cars that orginally came with pollution-control devices. Owners are required to keep these cars tuned to original standards/specifications. At least this law is not "changing the rules" on anyone.
One negative consequence that I can imagine is that more rodders and modifiers will now be directed to chopping up (actually, I guess the better term would be rodding-out) old metal.
Curmudgeon
