Ok i ordered a muffler and cat for my 92 SSEI last night. Now i dont have a tig welder or anything all i have is a regular old torch welder and an arc welder and everyone ive talked to says not to use either of those. My friend told me that you can buy these sort of clamps and that he used them on his car and it works fine. Is that a good idea? Any other ways i can do it because nobody i know has a tig welder and i dont want to have to pay someone to do it.

No arc, no oxy/acetylene. You can use the clamps if you must, but I don't like them. If you do that, use some of that cheesy muffler mending tape first, then the clamp, and make DAMN sure you get them tight, or double-nut the clamps.

If you have steel rod, you may be able to carefully Oxy/cetyl it. Athough, I've never tried welding stainless this way. Do not try brass rod or solder, tho. Melting point is way too low