...Did this not too long ago on my 95.

1)  Get the car as high as possible.  I drove teh front up on ramps and put the back on jackstands.  Make sure it iis supported extremely well - you'll be doing some shaking under there.

2)  Disconnect and unscrew O2 sensors. If you have never disconnected the headers and H pipe before, be ready for a battle.  Mine came off fairly easy (one took some serious grunt) but yours are 5 years of rust older (and tehy do rust..LOL)  Get some good penetrating oil like Liquid wrrench or WD40, etc. and soak them as long as possible.  That will help.  A propane torch can help too, but WD40 is flammable, so I'd hold off on that.

3)  Unhook the airtube from the stock H pipe.  I tried neatly undoing it, but it came off except for about 1/4"  Spent 2 hors trying.  then got a small hacksaw and spent about 2 minutes and cut right through the tube near the H pipe.    I bough some heater hose (about $3.00 for 6 feet) and 2 small hose clamps and used those to secure the airtube to the H pipe air tube.  Works great and there isn't near as much heat down there without the cats.

4)  Loosen the header to H pipe bolts, but keep 1 in on each side.

5)  Do the same with the H pipe to catback bolts.  

6) Unbolt/unhook and hangers the H pipe may have (near the tranny crossmember)

7) take all the nuts off the H pipe to catback and slowly let it down.  I used a jack to help steady it.

8)  Do the same withthe H pipe to header bolts.  This is where the ack is real handy.  The hpipe is HEAVY!!  Probably 75-100 lbs.  Don't kock your teeth out with it.

9)  Once it's down, install is the reverse.  The of road is much lighter (maybe 10-20 lbs.) and easy to handle.

Also, I bought a used H pipe and it didn't have the suds in the back to connect the catback to.  I pulled them off my stock H pipe.  THAT was hard.  They were really rusted tight.  A pair of visegrips to hold the tab, lots of WD40 and a breaker bar and 5 lb. sledge broke them loose reall easy - just dont snap one of them.

that's all I can remember off te top of my head, just budget more time than you think due to the tabs and the rusty bolts.  It's an easy job is you think through it first.  Good luck
Jay
95gt