Do a DOWN PIPE? The only down pipes I've seen, are attached to a high flow cat. I could afford one of those set ups but I've heard they turn on the SES light. Do you mean have my local exhaust shop fab a down pipe? The Websights say it only gives you 8 HP, I've heard that the u-bend gives the L67 6 HP so is it worth the trouble for the down pipe and cat for 2 ponies? Or is my info wrong. Thanks For the feedback.

Whether it's worth it or not to you is your call. I wouldn't do it. But it is an option. I've heard the GP's already have a pretty good-flowing cat on them (correct me if I'm wrong), so that is out. Still possible, but not much bang for the buck. A good set of mufflers and a U-bend will do you fine for a while. If you get into some serious modifications and start really adding hp and torque to the car then you might want to fab up a downpipe down the road or even do a high flow cat.. But the extent of most people's modifications, it's really not that necessary.
In my opinion, I'd get a nice set of Flowmaster 50 series. Good sound and performance. I think there is a recent post of someone selling a pair. I don't know if they are gone yet though.

Would premium gas do anything for a GT or no?

You wont notice a difference performance wise youll just feel it in your wallet

Did the u-bend today, also had new exhaust from the resinator back, with a couple 50 series muffs. Sounds Good. Got the exhaust and u-bend installed for 350. Thats more reasonable. Hope my wife doesn't get to the credit card bill before I do! Spent 370 at pfyc, 350 at the muffler shop this week, 550 on some RE-750 Brigstones last week, 350 on struts and alignment the week before, oh yeh also had the fuel injectors cleaned , replaced fuel filter and oil change a couple days ago for 150.OH MAN! I better call and get the credit limit increased at the rate I'm going. LOL

that's a hell of a bill..........

So putting premium fuel into a GT will do nothing for it whatsoever?

Other than burn more expensive gas....no.

Putting in premium fuel will allow the max spark advance. This is one of those things that makes such a small difference the Levi dyno can't tell, however the time clocks at the drag strip will. IMO if the manufacturer recomends premium, use it. That is what the spark tables are calibrated for. Anything else will cause detonation to occur. The knock sensors will pull timing out but knock has to occur first. Casue and effect. Because of the way that the computer works it will always try and run the timing up to the knock limit which, without premium is substantially lower. Again, the Levi's won't know, and if it runs fine on regular go ahead and use it. Just know that you are leaving a little performance on the table.

Oh yeah, what type of gas you use doesn't matter as far as the supercharge itself is concerned. I'd say the dealer is blowing smoke up your friends ass.