-there are a ton of different cat-backs, and countless posts of opinions of them. The word on this site is GMMG or tru duals are the best you can buy. I have magnaflow and like it, especially for the $$. Some of the others you wont go wrong with are Corsa, Borla, and SLP.
Like the others have said, that is a low dyno. For comparison sake, my bone stock 02 dyno'd 313 hp, 328 tq. Ditch the Flowmaster, maybe mess around with the Hypertech settings (they're not really good for a whole lot, if any, hp though).
Well, all the adds NEVER stack up as advertised. I was EXTREMELY disappointed with the numbers on my first dyno about 2 years ago ... just wanted to go home and ******* cry.
Don't take it too hard. I made a few chnages and had it tuned and was at 360 RWHP/370 RWTQ with only MAC's/ ported TB/ORY. It was mostly in the tune. As everyone has said here, ditch the FLOWBUSTER and get the tune. You'll be glad you did.
Save your money, get a cutout(35 bucks, plus however much to weld it in) get a tune and your done dude. No need to go changing catbacks yet, just save your money man and do the cutout. You can also just run a bullet muffler off the back of your y-pipe as well. Thats also cheap, efficient, and sounds great.
The tune is important. It will help adjust your a/f back to where it needs to be, because when adding headers **** likes to go way rich. So do these 2 simple mods, and you'll be a happy camper!
Get a good dyno tune, and I' m sure your car will wake up. In my area, a good tune, depending on combination, will run from about $400-$500. Who we have here, is really good, and I' d recommend him to anyone. Hell-of-a nice guy, and know his ish. A good tuned really woke my car up. I picked up at least 15RWHP with his tune, byt my guess, and track times. The only way you will maximize your combination is with a dyno tune. I hope no one takes this the wrong way, but, IMHO, one can not get a tune, for THEIR car, over the internet. Each car seems to be different.
__________________ 02 Z28 NBM A4
Intake, exhaust, stalled, some suspension
12.6 @ 108 1.6X with manifolds - bangin' off the rev' limiter
"If you ain't first, you're last."
-Reese Bobby Talladega Nights
I wouldn't push the panic button exactly. Remember a dyno is a tuning tool. Without a baseline run, it's hard to tell what your mods have done for your car and you never know if it's a stingy dyno or not. Did you get an air/fuel ratio reading with your dyno run? If it's way off, I'd probably spring for a custom tune but I'd probably put that off if I was going to add a cam or heads later. If it's pretty close, chances are you won't gain a ton with it. Like others have said, the Flowmaster probably isn't the best flowing muffler around but the average gain for headers and catback is around 20-30hp total so I doubt a muffler swap is going to add up to a bunch.