6-8 sounds about right, I would guess closer to 8. You got a whole lot of SPL bushings.
My shop charged me 4 hours for installing:
- Coilovers
- Front upper arms
- Rear camber and toe arms
On another occasion for my G sedan (with rear steering), 4 hours for installing rear Whiteline subframe and diff bushings.
Taking into account for additional parts you have (endlinks, traction arms, additional SPL bushings), but with synergy for doing this all at once, I would guess 8 hours.
Relatively small price to pay for the parts you are getting installed though
