Nice formy! 315's on the back? Ya they are basically FLP/LPP knockoffs from my understanding but they are 1/75" primaries with 3" collector which is the same as pacesetter, hooker etc. I thought about going with 1 7/8" TSP headers but decided that the 1 3/4's would work for me and I get stainless. A few guys on LS1Tech (yes I am a member there, I'm 1FSTZ71 there, I'm on thirdgen.org, ls1.com, camaroz28.com and a ton of others lol) have run ebay headers and had very comparable results to pacesetters and such. I figure worse case scenario I lose 5-10rwhp compared to another brand but saved a few hundred bucks, I'm ok with that, just change the jet in the nitrous nozzle lol. I love my SFC's, it rides alot better on these bumpy dirt rodes by my house and the doors sound better when closing. I've ran them on most of my f-bodies and love them, must have! I actually have a cutout to put on tomorrow (manual) and gonna pick up an electric DMH plate from a buddy when I go down to orlando. Right now here is the performance mods list:

Volant Air Intake
1 3/4 stainless LT's
3" stainless y-pipe
flowmaster catback
egr/air delete
UMI subframe connectors
hypertech programmer (just use it to adjust speedo, fan settings, shift points, and shift firmness)
85mm MAF
Supposedly has an LS6 cam in it (previous owner said so) but I doubt it, it had stock manifolds etc on it. She runs really good though

I think that's it for now on the performance list. I'm gonna be bracing the rear control arms and swapping in 1LE bushings soon, tubular panhard, upgrade the front sway bar and all the bushings, SLP Bilsteins, new stall converter, gonna get a PatrickG custom cam to run for awhile until I build a new motor for it and an NX kit that I need to put on just to name a few things lol. I've got big plans for her. I've got a set of ZR1's for the rear and GTO spares for the front to run at the track, just gotta order some DR's for em'.