Trunk light issue sounds like the break switch to me.

Thanks for the response. Where is that switch located? Do you mean the switch behind the brake pedal, or is it another switch?

That balky 1st to 2nd shift sounds like the 1st to 4th lockout system that Chevy built in to their manual transmission systems to improve mpg.  There are devices you can buy to install in the wiring harness to bypass this, but my own experience says you can 'outsmart' the system with either of two similar approaches:

1. Linger in 1st a little longer before shifting to 2nd;

2. Accelerate a little harder in 1st before shifting.  In effect, if you reach 50% throttle in 1st, the system believes you are serious about accelerating and will let you hit 2nd.

Try these options before spending money.

Had the same issue with my 2006. As a previous poster did, I bought a "fuse" that installs in the underhood fuse block that disables CAGS. Can't remember where I got it. Also, after adjusting the shifter (easy to do per YouTube), I bought the "Anti-Venom" mod for about $8.00. It is essentially a copper gasket that installs on the rear diff. that takes some of the tension out of the linkage. Another easy fix. Finally,  for my last easy fix, I replaced the clutch return spring with a C5 OEM clutch return spring, which took some of the stiffness out of the clutch take-up. All 3 mods totaled less than $100 and made a significant difference.

Haven't had any problems except one spark plug went bad

Only major problem I have had is the shift-lock problem where it wouldn’t shift out of park (automatic).  I took the console apart to gain access (utilized several of the videos on youtube) and bent the tang on the microswitch and it works much better now.  I didn’t want to do the mod where some recommend clipping or cutting off the locking pawl so I drilled a hole in it and attached a small cable from it back into the center console.  Now if it ever shift-locks me again, I can pull on the little cable to unlock it.  That also works great if I am working inside the car and want to shift it out of park without putting in the keys and starting the car (with the emergency brake on) to move the shift lever out of the way for working on things or cleaning purposes.

I have a 2005 C6 Coupe with an LS2 400 hp V8 engine.  I’ve noticed that my harmonic balancer looks a little wobbly.  Not a lot, but definitely not straight as it rotates.  Not hearing any belt chirping or noise.  Big repair?  Costly as well?  What do you all think?  Please advise Thank you. 

Need it to replace transmission shift cable because of broken plastic cromet broke cable wile trying to install it 

My 2005 Convertible LS2 400hp with 113+K miles has had a fair amount of issues. I'll list a few. The fuel cap sensor wouldn't work correctly after my first few weeks with my then brand-new (March 2005) beastie. The dealership had to completely remove the entire rear end to get to it. The shifter would get stuck in park. Dealer fix. The DVD map and CD combo stopped working about 8 years ago (never had it repaired). The convertible top stopped working (at least it was up). It took a "reputable" high-volume Corvette dealership some 5 weeks and multi-repairs in the thousands to fix and it still hits the cover going up or down (have to reach back to move the bottom of the top). Never going back to them. A fair amount of small issues have occurred and been rectified over the years. Current issues seem to be the roof is making a loud noise when going back up and the auto-light sensor seems to want my lights on regardless of the ambient light. Going into the shop at my favorite dealer, Sport Chevrolet, on Friday.

Same here on my 05 

Would not let me shift from Park....Had to have Dealer replace shifting unit...