heheheheee .... I can't believe you guys are taking the bait and actually coming up with numbers!
Sooo .... while you're at it, let's set a government-mandated horsepower-to-weight ratio too. Let's face it, nobody needs an oversteering 2300 pound car with 200 horsepower that does 150MPH - of course, WE can all handle that, but it would be highly dangerous to other motorists in the hands of the wrong driver - say, a soccer mom with a cell phone.
If you guys are truly concerned with road safety, put your efforts toward improving driver education/skill. Newsflash: SUV's don't drive themselves. One small example: we've got millions of senior citizens on the road who have no better skill, reaction time or judgement than someone who is legally drunk and could be arrested ..... yet, that's completely legal and acceptable. Who's more dangerous - me in my 5000 pound SUV or an 80 year old man having a 'senior moment' while blowing a red light in his Honda Civic? And if you think that 3300 pound Civic isn't going to cause much damage, you might want to do a Google-search for 'physics'.