What about clamp vs. welding? I have a flux core wire welder (no gas) that I've played around with on a few projects. I'm not very good at welding yet, but getting better all the time. The system I bought is mild steel and not paper thin, so I could weld it. The problem is I don't really know now to do it. Do you get everything just right on the car, then tack it, and then bring it down and finish on the ground (car is on a lift)?

I was planning on clamps, but this just got me thinking that maybe I'll try welding it. It wouldn't be pretty...but no one sees the underside of the car but me.

My real concern is leaks. Can a beginner welder do this kind of a job?

I'm not going to the local muffler shop...they want $600 just to put my system on. They are known around here for gouging people.