Robert, I would seriously consider doint some of this yourself if you have the time.
Get some Mopar roller rockers, which are the same as T&D's for around $900 (sometimes find them cheaper) and put them on yourself. No special tools required, just a few sockets, remote starter and a little time. The money you save there will pay for your headers, which you can install fairly easy as well.
Gears, unless you are confident with getting the correct lash I would let someone do them, but all in all it seems like someone is trying to screw you on the labor charges. Again, I have never priced labor for these items, but it seems awful high.
I know Elite Motorsports in Florida was advertising Mopar roller rockers installed for a little over $1200 and T&D;s only cost a few hundred more. So $2800 is outrageous.
ps - also you can find complete diffs with 3.55's in them for around $1200 or less (brand new). Just bolt the entire chunk in and no gear swapping.