Laptops are crap and overpriced for gaming.
Alienware are chronically overpriced on top of that.

A different option:

If you need something you can move around easily, but that you dont actually need to use while on the move, then instead of a laptop build a small form factor (SFF) PC. People use them for LAN parties all the time, so theres nothing stopping you from carrying one around in your car.

e.g. buy a Shuttle XPC barebones system, add cpu, ram, dvd, hdd and two of the beefiest graphics cards you can find in sli/crossfire - and you will have the best of both worlds. Add a carry case and a small monitor (still large by laptop standards) and youre sorted.