Thanks guys for everyones help.
When searching threads for spacers for the DB6501's, it seems like almost everyone is in agreeance on skipping rear speakers and just running the components upfront.
TX - I would really like to listen to them first, but I'm having issues finding this set of speakers at a local shop, so I'll probably be going off the forums and internet reviews. They are rated at 92db, so i should be ok with them.
Looking forward to the change