That looks like a very nice head unit indeed.
I think I have devised my plan and budget. My budget is $300. First I will buy and install a quality head unit like the one above and see how it sounds. If necessary I will upgrade the front component speakers and see how it sounds. I am hoping that for the time being I can get away with new HU and front speakers and just direct the majority of the power to the front speakers. Then I can upgrade the rears and possibly add a small sub as I get the money.