I sent you a PM. I'm in Tampa and can do the work. I have the factory parts with less than 1k miles on them and have done 2 header installations on gen 5 Camaros in my garage. I have the tools and ramps to get the car high enough in the air to get the headers out. One question though - why would a shop charge $800 to swap headers out for stock manifolds and cats. That's really high. Was your car tuned with the headers on (requiring a re-tune with the factory exhaust)? If so, one of the best tuners in the nation is nearby in Sarasota....
2011 2SS/RS LS3/M6 RJT, GFX, ECS Blower, FSP Blower Cam, SW 2" headers/3" exhaust, 3.91, built by Florida Speed and Power 745 rwhp, 620 rwtq
2012 Silverado 3500HD SRW Duramax/Allison