Meerkat Exhaust Mod

Hi guys, I've bought a used exhaust so I can make the Meerkat mod to it without the chance of fu**** up my original, I've got the ver 2 PDF from Pete at Meerkat Mufflers and I've looked at Magoo69's post on the subject, so pretty confident. Only thing I have a question about is the mention in Magoo69's doc on the handling of stainless steel in his page one, are these exhausts actually made of stainless steel or are they mild steel?

"Meerkat Mufflers specialise in custom made, stainless steel motorcycle mufflers and exhaust systems for bikes of every shape and size."
I couldn't find if they made them in any other form of steel. Looks like stainless for all products. I could be wrong though. I'm interested in this as well for my old Thruxton.

Since the exhaust is the cat, I'd be shocked if it wasn't stainless. Keep in mind that there are a lot of types and quality levels...stainless isn't stainless.
Mind if I ask what you paid for a used exhaust? I'm looking to do the same, but the only ones I've found (on ebay) are pretty pricey.

I've just done the magnet test and it does look to be stainless, the reason I'm asking about the exhaust material is that I have a MIG and a stick welder, but not a tig which is required for stainless, a mig can work under certain circumstances, but can't be asked to tool up, so I'll get my mate to plug the holes up. I've been looking for an exhaust for my 3R for ages, this bike is just too quiet, but I don't like the ones that are on the market and I like the prices even less , in my view the original exhaust looks far better than any after market ones I've seen. I paid 167 quid for the exhaust on ebay, I thought that was a bargain as I've seen used ones go for anything up to 800, bonkers prices for a second hand exhaust.