how quick are these cars with ....

I seriously doubt there are or will be any rebates in the near future. I know a lot of people got their x-plan deals refused by dealers. Plus the GT's are selling to well right now for the dealers to have any reason to make it cheaper. I still see threads about outrageous dealer markups on GT quite frequently.

As for times. I remember seeing a few realy good drivers post some 13.4's or 13.5's with stock cars. It depends on what you mean by exhaust. I know long tube headers and exhaust are giving big power gains (25-30+ if I remember correctly). Shorties and X-pipe back are seeing around 15 or so depending on the system. I would assume you could knock off a few more tenths with gears and exhaust. But I think the different gear ratio will require a tune won't it? The car may not react right without it.

You could also check out this site http://www.jmschip.com/bullet.php they have some packages giving good results. Read about the silver bullet.

I had that problem as well. Then I realized that the 05 starts off with more TQ than my Cobra. And is only down 5 hp. And that is on regular unleaded vs premium. And since gas is getting expensive it would be nice to get better MPG and use cheaper fuel. And with reports of tunes for 91 octane getting you +-25 hp. I started thinking the 05 is a better car. So as soon as I find one. Or find out when I can order an 06. I plan to buy.