Thread: How bad exactly is an inverter?

Here's the deal, I'm planning out a carPC for a 90-93 accord that i plan to buy pretty soon. Anyway I made this other thread with a ****load of questions: http://www.mp3car.com/vbulletin/newbie/28004-review-my-plans.html#post218579, but I have a real quick question, and I didn't want to add to my already long post. Now, I have a spare computer, here are the specs:

Shuttle Slot-A mobo
Athlon 850MHz (the older slot kind)
384MB PC133 SDRAM
16MB Nvidia video card (this would be replaced)
Sound blaster Live! 5.1 PCI with digital SPDIF coax output
30GB WD 7200RPM HDD
250W Antec PSU (120V)

Now, as you can see, this is a fine computer for MP3s, DVDs, navigation, etc. It used to be my main computer and I used it for those things (except navigation of course). If I threw in a new video card, it would be an excellent carputer, except for the power supply thing. This computer would tuck away nicely in the trunk, so no problem there. But power is a problem. I here tons of horror stories about invertors, that they are loud, ineffiecient, unreliable, etc, etc. But you have no clue how much $$$, time, research, and fabrication this would save me if I could use this computer and an invertor, vs building an ITX-based setup. I really don't wanna half-*** this tho, I want the end result to be decent. So I figured this:

Here are the bad things about invertors (that ive read anyway), and my excuse/solution to each one:
Loud - I'll run a power wire from the battery to the trunk (with a fuse, and a relay so its only on when the ignitions on, to reduce battery drain) and hardwire it back there, so you can't hear it from inside the car.
Inefficent - I don't plan to use my carputer when the car is off, so if the alternator is keeping up with charging the battery, what's the problem? I'll replace the battery with an Optima yellow-top anyway (I've heard the old accord batteries are flakey so I put a new one in the budget), so I don't think this is a problem
Unreliable - This could be a problem, but how true is it? I'll spend anything under $100 for a decent one (or is this not enough for a decent one), there has to be at least one brand thats reliable (I hope)!

So how bad could it be I figure. It would save me so much time and money, maybe invest in a nice Xenarc instead of the Liliiput, and I think the end result is a much nicer, faster, computer. So let me know what you guys think!