my main thing is to fix the leak in the y-pipe and to replace all rusted bolts on the pre-cats, that way if i decide to sell the car, and install new pre cats, then i could possibly install them myself since new bolts will be installed. Does that make sense lol.

 

Soak it in soap and water (I would use a degreaser) and rinse with distilled water or brake cleaner. It's a practice (old school) people use to pass emissions in retarded places (like california) or to be legal . If the plates are good, then there's no point replacing it when cleaning restores functionality.
I suggested it just for fun and might help flow if it's dirty.

If you use defoulers, then it doesn't matter if you sell b/c it will still pass emissions.

 

Well I ended up going to another exhaust shop, they told me exactly what needed to be replaced. The y-pipe and flex section was fine, i saw for myself, the leak was coming from a gasket where the main cat and cat-back meet at. THe previous exhaust shop wanted to replace the y-pipe, rear pre-cat, main cat, things that didnt need to be replaced. These guys said i only needed to replace the rear pre- cat/ if i buy it online its like $177 or less, they will install it for $200 labor. I also asked about gutting it, only thing they can do is replace the pre cat. SO i let them fix the leak, ran a small peice of straight pipe at the rear of the main cat and the catback connection because the flange would not seal with the new gasket. The car is quiet now, a little too quiet lol, feels almost like a new car.