For one thing it is targeted for most of them ricers out there, many of the Honda Civics and the like after they are modified don't pass emisions anymore, because everything in them has been gutted or changed to make more Horsepower, which in my opinion the car don't have much of to begin with. It can also effect hotroders who want to cruise around in their boulevard street machines, I kind of find it strange to think they would Impound a vintage Mustang and sell it just cause the engine wasn't the specified one that came with the car, engines don't last forever, you sure there isn't something more to that Jim? The 3.3 and the 3.8 look so identical that if you put on the manifold that says 3.3, you wont be able to tell if it is a 3.8 unless someone tells you, it's the same design, uses the same parts as the 3.3, the internals are a little different, but hey I doubt they will be pulling apart the engine to look inside. If they dyno test it they might see something different, but I highly doubt they would. I think it could be pulled off with no problem. Matter of fact you can bore and stroke a 3.3 and get a 3.8, that's all Chrysler did. _________________________________________________________________ MSN 8 helps eliminate e-mail viruses. Get 2 months FREE*. http://join.msn.com/?page=features/virus