I want your welder advice!

[formula350]

I'm about to start doing metal work on 78 bird
But I never used a welder and all my knowledge is from what I've found looking around the internet
Some of the things I need to know before diving into this:

1. What kind of welder should I buy?
I'm looking to it and from what I've found I'm looking for a 110amp 18g mig?
Im on a budget and I'm not about to spend $1000 on one, but Im sure a harbor freight welder may not be up to the job
I was looking at this welder here and so far I think this may be the best for the money?

http://m.grainger.com/mobile/details/?R=2WDP5



Advice please?

I'm going to be replacing floor pans, quarter panels, smoothing the firewall, and adding mini tubs.
And some other various small tasks.

And I would also love to hear any good advice for a beginner doing work like this. What to look for, beware of, tricks, tips, other tools needed, technique for Srong welds anything on the subject.
And where should I start my work from. The floor pans?
And when I do the work should I focus in one area at a time or do things all at once?(like when replacing the quarters, tub them at the same time or do them one at a time?
Thank you I hope to hear your input.