I have 2 that will be going up for sale, I WANT MY CAR TO SOUND GREAT GOING DOWN THE STREET NOT GIVE ME A HEADACHE INSIDE THE CAR EVEN WITH THE CONV TOP DOWN!!!!!!!!!!!! THEY SUCK
I have the RamAir cast iron headers and I then went with Magnaflow, Magnaflows are great if you love the old school sound of glasspacks, they have a nice rumble cruising and when YOU GET ON IT THEY EXPLODE TO THE WORLD BUT NOT IN YOUR HEAD LIKE FLOWMASTERS.
In case you didn't get my subtle hinting I hate Flowmasters.
I had Thrush turbos, they came with the car, never got the sound I wanted, if you t sound a tad over stock with slight and I mean very slight hp gains then those may be right for you. If you want your car to run cooler, like 10*F cooler and get a huge gain in HP and TQ I would go with the cast iron RamAir exhaust manifolds and Magnaflows, get the manifolds from RamAirRestoration link below. I've had headers, not crazy about them anymore, the factory RA exhaust was well engineered by Pontiac and they take away more heat, RAR will ceramic coat them so the heat does not go into your car and underhood it goes down the exhaust pipe which increases velocity and they are not as challenging as headers to install but you do need the RA oil filter set up.