Ok, I'm a college student and something of a welding n00b so bear with me.

Currently I have a lincoln Weld-Pak 100 thats been converted to MIG, a Lincoln Procut plasma cutter and a Hobart 300 Amp 3phase MIG that I'm trying to trade (bought for a good price but want something that will run on single phase...see my post in the equipment FS forum). My dad and I also share a full oxyacetelene cutting/heating setup and a Craftsman AC Buzzbox set up for stick

I have recently had the opportunity to buy a Hobart Plasma Arc 400D console for very cheap (probably inside of $200). Now I searched and read quite a few posts about plasma welding but I'm still left with a few questions that I'm hoping someone can help me with. I was considering buying a tig setup but at this price it seems like I could probably get set up completely for less than the cost of a used miller econotig, and have more capabilities. If I went the tig route, I would probably plan on getting an AC/DC CC power source that is capable of doing stick and then add on a HF box with lift arc/maintain arc features and an afterflow timer.

I understand that the console by itself won't do much, and that in order to make things work I would need a CC voltage source as well as another argon or argon blend bottle and another regulator (I already have one for my mig setups), so here are my questions:

1) Would it be possible to get a plasma cutting head and adapt it to work with this console? I don't really need to, since I have the lincoln pro cut, but I am curious to know the answer. Also, would I need to use a plasma gas (like argon) or could I just use a pressurized air source with a regulator (like my current plasma cutter does)?

2) Would it be possible to hook up a tig torch to this console and use it to start arcs so that I wouldn't have to scratch start them? It seems like this has the features similar or identical to a high end HF box for a CC supply (after flow timer, port for an external controller like a foot pedal, etc) except that its designed for plasma welding

3) Would this console be picky about the torch attached to it? I was somewhat scared by some suggestions that a good torch for this console would be 1000+ but it seems like you can get used plasma welding torches on ebay for around 80-120$ with cables, but they aren't hobart.

4) how suitable would plasma welding be to doing bodywork on a car? What about welding up trailer frames composed of 3/8" steel?

5) How suitable would 75/25 Argon/CO2 be as a plasma gas as well as a shielding gas (assuming I bought another regulator and split the bottles output instead of buying another bottle)? Assume just for welding mild steel here.

6) Would I notice a significant difference in welding aluminum or stainless assuming I set this up properly to do plasma welding as opposed to welding them with tig?

Thanks a lot for any help you can offer