Is this something I can do with a decent set of tools? If there's welding involved, I'll have to pay someone else to have all the fun.

The way I imagine it, the job shouldn't be too hard: you just take the thing off and put a new one back on, right?

Another thing:
I care about the environment. I really do. But, I also care about my wallet. In the timely case of a tired CAT and the California DMV, it looks like my wallet pulls more at the compromise.
We all know Volvo catalytic converters are not very economically priced. Since the wallet wins the compromise over environment, are there any compatible CATs that cost around...say...50 bucks? (Los Angeles / Southern California area)
I only need it to pass the smog test. I know it's not environmentaly ethical, nor does it sound like good-old volvo integrity. But the car's ~265,000 miles old and needs new valve guides anyway.

Thanks for the time, Bricksters!