The reason I took off the muffler is because I think I'm getting a little old for the "hey, listen to me" kind of a car. I never thought I'd get tired of it. My setup (HKS intake and muffler, B-pipe, Y-pipe) sounds very aggressive and nice, but it has grown rather tiresome after the addition of the B-pipe and Y-pipe. Just for fun I put my stock muffler back on (gasp!!!) to see how it sounded. I actually like it and I can't tell any difference in power deliver throughout the powerband...even in the 90 degree weather we're having right now. It still spins thru 1st with a 1800 rpm clutch drop and barks hard into 2nd. You can still hear the exhaust a bit because of the y-pipe and small resonator in the B-pipe, but there is no drone anymore. Unfortunately I've got a stupid Bosal tip on the stock muffler that I need to cut off. I want something more angular and square like....and smaller diameter (4" is too big for me now).

Here's some interesting measurements I took:

Stock muffler pipe internal diameter 2.15" outer diameter 2.35"
HKS muffler pipe ID 2.25" OD 2.45"
Courtesy B-pipe ID 2.30" OD 2.50"

Since the HKS muffler isn't exactly a straight thru muffler (like the stock muffler) and the internal diameters are all relatively close, maybe the stock muffler really does only loose 1-2 hp over the HKS muffler. Maybe all the restriction lies in the B-pipe and Y-pipe. We'll see how she does at the track later this month.

Dave

The HKS doesn't claim to give you any additional HP to start with.

put it this way:
there is nothing you can't beat now that you can before

I'd figure the HKS would be worth a little something for hp since it is a smaller muffler, has slightly bigger piping, and appears to have less internal obstruction since the muffler gets really loud with other exhaust mods. I thought it would be good for 2-3 hp with other mods. Maybe not. I thought they claimed 3-5hp with the muffler, but maybe that's just individuals here in the forum. It looked good though, but I might just have to get rid of it now.

Dave

has ne 1 dynoed that yet?

Dave, I'd be interested if you're gonna sell. I wrote you an email.