A color wheel is not so difficult to put in - it's dismantling the unit to get to the color wheel.. While $500 seems to me a little bit high for your area it might have been about average and $127 for labor is probably a pretty good deal if he did this as an in-home repair figuring his time installing the new lamp into the housing and the housing into the unit, plus travel time to and from the shop.
The noise you're experiencing could be the fan and not the color wheel.. Easiest way to tell is take the back off and as the set is turned off unplug the flat ribbon cable going to the color wheel. If the noise quits immediately it's color wheel if not guess what - it's the cooling fan...
A shop would be the only I would know to advise you to have this repaired - I'm a CET myself and it's a pretty difficult task taking one of those DLP format projectors apart. And I've been at this more than twenty years. But you can test whether or not that's your problem and go from there.. If you have to have the color wheel replaced have the tech look into having it rebuilt and see if Tri-State Module services that wheel.
A good way to research techs in your area is with NESDA (National Electronic Service Dealers Association) here's a link:
Hope this helps!