thanks for the help with the oil filter and timing chain questions! Now to part 2.....The car started vibrating wildly above 65 mph. Below 65 it was smooth as silk! The vibration is not limted to the steering wheel. I took it to the local tire dealer who balanced and rotated the tires (Michelin). I took the car out on the interstate and voila! It was worse! The car started vibrating wildly at 50 mph. I took it back, the MANAGER checked the front end and said that everything was fine in that department, rebalanced the tires, took the car out for a test drive, brought it back and said that it still vibrated (above 60 this time) and that it was probably a failing transmission(it doesn't have any other nasty symptoms) or a bad driveshaft and (or) bad flex discs or motor mounts. A friend of mine said to take it to the dealer because (and I'd never heard of this) they balance them while they are on the car.

Does any of this make any sense and it is it an extremely expensive problem?