the install price he quoted isn't outrageous, but it is kinda high. I don't think he quoted you high because he is upset with you, i think he quoted you high because he may not be as familiar with the equipment as what he carries. That means it may take more time to install properly. This matters because he can only now warranty his labor, not parts and labor. So he has to make sure the job is done right, can't afford to damage your equipment. You'd be pissed if something went terribly wrong.
in addition to this, you have to understand what you are saying to him. Money talks and you are communicating you don't trust his judgement in equipment to use whether you can afford what he wants for you or not. I don't blame you or him, its just business. the retail car audio market is getting raped right now because of greedy distributors selling direct over the internet instead of like back in the days when you could only get stuff from dealers.