noise, the 603 wins hands down. I have NEVER gotten any drive through problems with the 603. I nearly always have to shut off the car in a drive through with the 617.
vibration? in perfect tune, they are very similar vibration wise. if the car has vibration in a 617, it needs something. either valves adjusted (which the 603 never needs) or injector problems *(fuel filters can cause vibration as well as motor mounts)

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!