Well I removed my hedman longtubes and went to hedman shorties and y-pipe. I also installed a Catco Super Convertor and a Catco O2 Sensor. First I must say yes I lost power that I can feel, but the noise is so much more nicer for a daily driver. It sounds deep through the RPM and never gets raspy and doesnt pop. You could truely leave it just like this and be very happy.

As for the install itself. It was very easy. I did as following but remember some of it was because I was removing longtubes but I promise you it made it easier and its not hard work. It was all done on jackstands in a driveway.

-Disconnected battery (VERY IMPORTANT....when you remove the starter your gonna know if you didn't do it!)
-Remove oil dipstick by twisting and pulling up
-Loosen all header bolts (or for most people without longtubes...remove all cast iron bolts.... some need to be done from the bottom...you will be in tight places general thinking will get you out of the tight spot. Try vice grips on a socket)
-Remove the passenger engine mount bolt (VERY IMPORTANT YOU DO THIS BEFORE REMOVING STARTER...it gets in the way)
-Remove the flexplate cover and then remove the starter.... (try not to let it just hang there)
-Remove sparkplug wires, sparkplugs, and all sensor wires including o2 sensor
-Jack the engine up with a hyd. jack so it tilts
-For putting the shorties in (not gonna get into the longtubes) go through the bottom for the passenger side headers goes right in.
-Lower the engine back down once the headers are all bolted in...you will notice certain bolts need to be installed first because you will crossthread them if you try later
-Reinstall the engine mount bolt
-Remove the driver side engine mount bolt....jack the engine up so it tilts....install from the top. VERY easy to go in...
-Same with the bolts certain ones need to go in first you will see what ones
-Reinstall the starter, flexplate cover, sensors, and sparkplug wires.
-Reinstall the dipstick...this is the hardest part...yes the dipstick is the hardest part...if you bend it at all near where it enters it will not go in I promise... I would recomend getting a new one anyway there not exspensive... when I have installed the longtubes and reinstalled it I had a buddy guide it in the bottom and I put a socket over it and beat it with a hammer to get it back in...the second time around it wouldnt go in so I had to get a new dipstick.
-Now you need to decide where you want the o2 sensor. Have a buddy hold the y-pipe where it will be and mark it.
-While its up there decide where the remoavable pipe on the y-pipe needs to be and clamp it there.....weld it later.
-Have a shop or if you know how to weld cut a whole out for o2 bung and have the o2 bung welded in.
-Installing the y-pipe it straight forward just make sure you have the flange on the y-pipe where it comes apart before its welded....
-After that clamp on your cat and then your cat-back...

All was done in 6 hours with two guys and us almost burning the shop down with the welder and cleaning up all the fire est. powder that went everywhere.

As for parts I used the following:
-Catco Super Convertor Universal (2-1/2" in/out) no air tube (I dont have smog equipment its useless in states that dont visual)
-Hedman Shorty Headers (Ball and Flange) no-air
-Hedman Y-pipe (Ball and Flange)
-Summit O2 Bung
-Percys Crush Gasket

If you have any questions please ask or if anyone noticed I left anything out let me know. If you want pics I will get them but im lazy.

 

That was freakn fun. My first time welding too

Just to let you guys know, It's the second header bolt from the front of the car on both sides that need to go in 1st

 

where do you put the o2 sensor? does it go on the header or the y pipe? and where exactly, if u had a picture that would be awesome