I've done sound for about 40 tv commercials. And probably most of them were shouty car/truck commercials. I've also done a number of radio-only spots.
Trust me, it's not so much about the mic. I used all kinds of stuff and I've seen others use all kinds of stuff. SM7s and RE20s are common for radio spots mainly because they are good broadcast mics (they are pretty uniform, handle plosives, not too sensitive, durable, etc.) so they just happen to be there already at the stations. But radio spots in pro studios, I've seen everything from dyanmics, to U87s, so shotguns... doesn't seem to matter too much for the end result. In fact, when having logistical difficulties with a certain key V/O talent, I've litterally recorded the guy (who was awesome and well worth the money) in a freakin' parking lot with a medium grade lav (wireless even!) and it was all the same.
There are two main factors:
1) the talent. You either have good v/o talent or you don't. It's not a technical thing. That voice is that voice. There pretty much isn't anything you can do if they can't give you the voice.
2) As I mentiond before, slam it with compression. Soft-knee works best and a high ratio. Follow it with a limiter. You might be able to get away without the limiter if you use agressive enough compression, but I prefer adding the limiter (which can be a better approach if you have broadcast spec reqs). One other thing I might add is that even though they often sound deep voiced, you still often have to do some rather serious HPFing. Like 150Hz. The reason being that you typically have to cut through a bed of music and you typically are recording with a lot of proximity effect. The deep sound is generally the v/o artist so it will still sound like a deep voice.
So assuming you have v/o talent you like, the key is just the compression as I mentioned. And depending on the voice/usage possibly some heavy HPFing.