Here's the skinny on the tube sizes: CE makes 'bars' with 1-3/4" tubing and they make 'cages' with 1-5/8" tubing. They told me why they do this when I was up there, but at the moment I don't recall what it was.
My cousin is a welder by trade and he's installed many bars & cages in his day. He swears by CE's kits. Says he's never had any issues with them. Said they're always an excellent fit. That's not to say that MM aren't quality also. He said he's never done one of their's. I wouldn't necessarily judge quality by $$$. A Kenny Brown 8pt cage is around $500. Mild steel is pretty much the same wherever you go. My car's at CE/Moroso right now getting an 8pt cage. They didn't have production jigs for 94-98 so I was able to get an awesome deal for donating my car for the design fit. Got a couple of pics posted here:
http://eastcoaststangs.com/fusetalk/...&threadid=2253
I'll post more when it's finished.
As for learning to weld...Do you really want a roll cage/bar that you someday may rely on to save your life to be your 1st project?? I wouldn't. If you do though, it must be MIG welded for NHRA/IHRA cert. So learn to MIG and not stick.
Good luck