Need help to choose headers

Hi, I want to replace the complete exhaust of my '98 convertible LS1 Trans Am and I can't decide myself for a system.
The planned modifications will be intake (filter + MAF), exhaust (from the headers to the tips) and a chip tuning. Nothing more.
Now I can chose between LT headers (like the SLP), middle headers (Bassani or MAC) and short headers (JBA or Hooker).
LT headers should give more power but I understand that the installation and the floor clearance will be an issue. True?
Apparently the short headers aren't giving that much power, what about the middle ones?
The Bassani system looks good to me, does anybody have experience with it? I would take headers, cats and Y-pipe (see them at www.tbyrnemotorsports.com).
Because of only Filter and MAF, is it really necessary to replace the cats? The cheapest solution would be to short headers, stock cats and a SLP Y-pipe…

I hope someone can give me some advises! - Thanks

I know several people with Jet Hot coated Mac mid-length headers. All of them are very pleased with them. I want LT's, I want to gain the most horsepower possible from that mod...