I just purchased my second Caddy, a 01 DeVille DTS. Got it from a dealer with 74K. It was too clean to pass up. I got my 99 D'Elegence from a dealer also and pretty much did a full tune-up within 90 days. Spark plugs, plug wires, ignition coils, air filter, and fuel filter. I'm thinking of doing the same with my new DeVille DTS except I'm thinking of holding off on the coils due to cost. Anyone see a benefit to changing the coil now as opposed to waiting. I'm not experiencing any reasons to change it, just looking to give her a tune-up since I don't have a record of it being done recently.