The 5000 has GPS capabilities, not GPS. You need another unit for GPS, but it has area shot (basically directions). The 4000 has 5V pre-outs, the 5000 has 8V. The 5000 also has a 7 band semi-parametric EQ (each band has 3 selectable frequencies with an adjustable "Q") so it's got some really nice sound shaping capabilities (better than the 4000 3 band graphic eq). The 5000 has a better display, 24 DAC CD reader and can take a memory stick (4000 doesn't have those). The 5000 also has DSP and just more sound control over all.