What makes a weld job a quality weld job?

[BlackFireN2O]

Thanks for all the info and it is really helping aid my decision. But i have to ask if i got the book read it from cover to cover, then took a welding class, would i be competant enough to tackle all of the welding that is needed in building up my mustang? I mean if i need 25 years of practice to weld things good then i think i might have to resort to paying someone to weld my stuff. But i'm scared that if i go to a "pro" then might not even know what their doing cause there are shops that do not do quality jobs. Anyone know a good welder in the New York area, what is the average price for a roll bar (8pt) and fram connectors? Plenty Thanks!!