wow - i realize my question was like driving up to a bar in Texas & asking which is a better truck, Ford or Chevy. I'm leaning heavily towards the L6 (that's W104? ..i've gotta learn the models) more due to low mileage, impeccable interior condition, full maintenance records with a single PO, potential transmission higher longevity/lower R&R cost, and general "honest car" condition. The '99 MY is about the newest I would be able to go financially as I live by a cash-only car purchase philosophy & at that tend to devalue any & all practical cars to be never worth more than about $7-9K (fun, heavy maintenance antique/sports cars are worth more in my twisted mind!).

Thanks for the input, folks. I'm sure I'll be reporting back with my findings and hanging around in general to absorb tech info.