Another thing to consider is that with modern Avionics, you can get a whole lot of information in a much smaller space. I figure I have 3 years before thinking about the panel for real. A lot of changes and new products will come out between now and then. There is already talk of black box radios from one company which would be controlled by the EFIS. This would totally eliminate the need for radio panel space.
Go for the -8 and don't worry about panel space.
