the smarter thing to do would be to have a cutout placed in the I pipe, so you can be loud when you want to, and quiet when you need to. Should feel a little from the seat o' the pants dyno, should change fuel economy too much either way.
__________________ 09 G8 GXP M6 and 86 Buick Regal T-Type
I wouldn't just take off my muffler that would dump all the sound under the car and make a noisey cabin all the time a cut out is a good idea though if you want it loud and quiet or you don't have enough money for a cat-back.
1999 Z28 M6 | MTI Lid | SLP LM1 | Free Mods | UMI STB | UMI SFC's | Short Stick | !CAGS | 20% All Around | 4.10s | Pacesetter LT's | ORY | Next Mod: LS6 Intake
I have no muffler on my TA and had tips welded onto in and I love it. Sounds a lot atter then stock.
__________________ 1990 Trans Am GTA-'98-'02 Ram Air Hood w/ K&N Airbox- Sits 1995 Formula- Mods, Mods, Mods- SOLD 2000 Trans Am- WS-9 Hood, ShiftKit, WS-6 Rims, Custom Exhaust- SOLD 2000 Camaro Z28-Forged 347,TTi 76mm Street Turbo kit,-FLOODED 2004 GTO- Barbados Blue, 1 of 302 A4s produced. SOLD 2011 Camaro 2SS-RS - Just Your Average Heads, Cam, FAST, and Nitrous Fed LS3
i dont believe so it should be fine i know with my jeep 4.0 i ran no cat and no muffler and it did not make enough back pressure. but your car should be fine no different then the guys that drive around with their cutout open. i know the slp or bullet exhaust is almost like having no muffler and they dont cause any problems so i would bet that you are ok. there is a guy on here that has his z straight piped you could try to find him and talk to him
i have stock manifolds, gutted cats and an SLP loudmouth II with gutted resonator and i ran a 11.86 at 119.7 with spray and drag radials. as for gas mileage... i feel it all depends on how you drive your car. btw... ITS SOUNDS NICE!!!
__________________ 1999 Chevrolet Camaro M6
MTI Clear Lid, Smooth Bellow, TB Bypass, SLP Y-pipe w/gutted cats, M/T ET Street DR (THEY HOOK!!!)