I'm thinking of taking on my 99's exhaust problem myself. To recap, blew some pieces of the cats out the exhaust, so I need new cats welded in, and a new muffler, and I'm guessing new pipe to delete the resonator.
I've got a friend with a welder that offered to help out, so I'd like to see if I can save some coin and take his offer.

Questions:
1. I'm guessing the exhaust system is backed up a little from the cats being stuck in resonator and/or muffler, should I worry about anywhere else?

2. Can I/should I detach catback in the mean time to relieve pressure? Would I lose too much back pressure? (won't drive much at all, 2 miles max rest of week)

3. Cats: i've been told universal 2.25" in/out round cats will work, so all I need is to have a shop cut them out, so we can weld the new ones in?

4. Resonator: have read I can/should delete it altogether, doesn't effect back pressure? If so, need the shop to cut this out as well, and purchase new pipe to weld in its place? If so, what exact kind of pipe and from where to buy?

5. Muffler: have the shop also cut this out and simply weld in new muffler? Any tips on a "value" replacement? Local auto parts store? Would like to do this friday or saturday, so probably not a shipped option.

Anything else I need to know or purchase to take this on? Total noob here and have never messed with exhaust or welding, my friend will probably do the welding.

Thanks!

 

Ok, I went through a very similar thing, but my cats were/are fine so all I did was mess with the rest of it.
My muffler was rotted and very very loud.
I shopped, researched, talked to people about mufflers...
Since your friend can weld go buy your universal cats and have him cut out the old and weld in the new.
Then take your old to the scrap yard for money, cats go for big money because of the platinum in them.
Then since you are also getting rid of your resonator (I left mine in) take the truck to a muffler shop and have a new exhaust put in.
Once you remove the muffler and resonator you will have removed 3/4 of your exhaust system anyway, so might as well do the whole thing.
I just had my muffler replaced, $110 out the door.
It is a Walker Quiet Max SUV muffler, so its nice and quiet and big enough for a V8.
If you buddy has a pipe bender you can go to a autoparts store and buy a 10ft straight pipe for around $2 per foot.
Then you cut and bend it to fit and then weld in the new muffler.

The OEM exhaust is stainless steel.

Here is what I was originally going to do.
I was going to remove my whole exhaust from the cats back.
Put a new turbo type of muffler with a single inlet and a dual outlet where the resonator is.
Run straight pipe from the cats to the muffler and then run dual tips from the muffler out the back.
I think it would have looked really cool and given the truck a nice deep throaty sound when accelerating.
However I was having a very hard time finding a performance type of muffler that will not "drone" while cruising that was still affordable.