Well Idunno bout 10 speakers myself in older ones...is the mach460 8 speaks? Old Mercedes had 10
some component sets with seperate woofers and tweeters would be sweet with beefed up ones in back like 6X9 Cerwin Vegas or Pioneers...Why exactly would you put 4 6X9's in trunk by the way? is it a hatch or trunk? Can't imagine hearing 6X9s from inside the trunk...As far as head units I would reccomend pioneer. I just put one in my Lincoln recently...its like the second model up with multicolor and detach faceplate...great power and I have driven down lumpy dirt roads and not skipped once. Crutchfield.com is the place to go