If I had a $7500.00 budget,I'd buy something new with a warranty.That's a lot of money(to me anyway)to fork out for something that may crap out tomorrow with no recourse.$7500.00 will buy you a great audio section for a HT system.This of course is just my opinion.Good luck with your project.
New HT system
Looking to build a dedicated HT, 2 channel not needed for this endeavor. Will be buying preowned from the gon. Need advice on 5.1/7.1 speaker system and receiver vs. pre/amp combo. Budget for audio $7500. Also, interested in HD 1080p projector for $3500 or less. Again will be buying preowned. Room 15.5 x 13.