Again, this is a stupid false equivalency, in that SUVs are not intrinsically designed for any dangerous purpose. Assault weapons and high-capacity magazines are designed to provide increased killing power. Again, I am not advocating for gun control measures and own several "high capacity" magazines for my Glock 17, but your analogy is silly.
How is it false? So guns are made for killing... so what? Not all killing is bad, just like not all driving is bad. The fallacy is in placing the morality of driving over the morality of using a gun. In placing cars in a different category than guns because of some supposed "need" or "usefulness" that is apparently superior to the "needs" and "usefulness" of guns.
I would argue that the need for extreme self defense, say, after a natural disaster like Katrina or in a situation like the Rodeny King riots is just as relevant as the more mundane daily needs for a car, if less frequent. This need could easily be met by "assault weapons", as it was in both mentioned scenarios.
Here's the arguments I'm hearing for banning high capacity magazines/assault weapons.
1. They are not "needed".
2. They are dangerous.
So why don't we ban other things that fit that criteria? And don't say "because they serve other purposes" as we've established that "they are not needed", ergo their "purpose" isn't enough to justify it.
1. An SUV is not "needed". It has no practical "purpose" (given the availability of Jeeps, pick-ups, and minivans).
2. An SUV is dangerous.
1. A pocket knife is not "needed", unless one is doing something that requires a knife.
2. A pocket knife is dangerous.
1. Nail clippers are no "needed" unless one is clipping nails.
2. Nail clippers are dangerous in certain contexts.
My point is the logic behind the arguments in favor of banning assault weapons and high capacity magazine is the same "logic" that's brought us beyond dumb TSA regulations and UK-style "need" and "proportional force" arguments where people get locked up for defending themselves. The argument invalidates itself because it's general, and if applied generally leads to absurdity.
The only attempt to specify its scope consists of an abstract moral, philosophical argument that guns are somehow different from other dangerous items due to their range of potential uses. If that's the case, then the argument is no longer about saving lives and dangerous items, but about philosophy and subjective impressions.
Therefore, I find the "need and danger" argument to be incredibly weak as a grounds for practical legislation.