I'm not sure, but I think car-jacking is a UK phrase, so I guess it fits the extension well. The first thing that came to mind was a forum on exchanging tips on car theft..... But that's hardly a reputable base for a site. You could focus on car-theft prevention though... Good luck!
I was under the impression that a carjack is a *tool*, nothing to do with the verb carjacking which is common in South Africa.
Assuming it is the tool, then I think it has quite some value.
A catchy alternative to 'assault-and-battery-on-the-road.co.uk' ?
A fan site for GTA (the game) perhaps. The game had a context to excuse the nastiness. I can't see a use as a formal use, a jack tool site, cos the negative meaning is stronger.
And .co.uk is ã35 per owner transfer, which soaks up my appraisal. Sorry.