Fow what it's worth, here is my recommendation and opinion.
1) Nothing beats TIG for control of your weld on small, detailed work.
2) Cheap-o welders are a waste of money.
I use Miller equipment. I like it.
I've used Lincoln, and have no complaint there either. I just got a better deal on Miller.
This unit, the Dynasty 200 SD, runs on 110v, and is adjustable from 1 amp to 200 amp. This unit does both TIG and SMAW (stick), and has the squarewave AC for aluminum welding. This unit should weld anything on your car, unless you drive a D9 Cat. Heck, at 200 amps, it'll weld that too.
SD model on left. DX model on right has a few more features and a little higher price. They are lightweight, and probably the only welder you'll ever need. But they really ain't cheap.
If you don't plan on doing a
lot of fab work, I really would farm out the job. Even though you have a job of a secret nature, you may be able to find a trustable Pelican to help you. Not me, though. You really can't trust me.
Besides, my aluminum skills suck.
Disclaimer: I don't work for miller, not do I have stock in the company. I just like their products.