I still like Throckmorton. ('Course, I did suggest it.) But it sounds like your Jeep is going to come down and pound on someone.
Personally, I think that Throckmorton is easier to remember and pronounce. It kind of rolls off your tongue--and I'm not saying that just because it was my suggestion. You pronounce it like it is spelled. I liked Philip Pullman's name for the bear, Iorek Byrnison, and how he had a whole culture for the panzerbjorne, but I found their names difficult to pronounce. That did create a nice, foreign, non-human feel of a culture in the book, but I think it is still a little confusing as a name of a car. How do you say Iorek? Is it I-O-rick? Or E-rick? Or I-wreck? I suppose it doesn't matter, but I like the simplicity and power of Throckmorton!
Then again, it is always fun to have a story behind naming your car. I do. So perhaps the story behind Iorek Byrnison, that he is a warrior polar bear from a YA fantasy novel, is more interesting than, "Some girl I know suggested Throckmorton."