WD Passport Studio firewire problems (not cable)

Greetings,

I own DELL XPS M1330 (pre santa rosa refresh) laptop.
I recently bought external 2,5'' hardrive WD My Passport Studio 500GB, which is Firewire 800 capable (also USB 2.0).


Now I am thinking about returning the drive (so I can't open the box and test it) because of all the info I've read here.

1. DELL XPS has only firewire 400 port

- so no use for firewire 800 specification of a drive for me, and I've red here:
You're not going to find FireWire 800 on anything but an Apple..
- USB 2.0 is the same speed as firewire 400 anyway (and somehow more on Vista)

2. DELL XPS has only 4-pin (not 6-pin) firewire 400 port (mini-firewire) which isn't self-powered (unlike firewire 800, or 6-pin firewire 400)

- which means I need to get a power adapter for my external 2,5'' hard drive, which is not possible to do.
- and I wouldn't buy portable hard-drive if I wanted to carry power adapter with me


That means the WD My Passport Studio is useless for me (is great drive for many others), I could get My Passport Elite instead - which is USB 2.0 only but is cheaper, ligther and more compact.

Thanks for any answers which hopefully clear external drive firewire usage with XPS notebooks (no go w/o power adapters).

edited: added clarifications