I'm currently looking at a 1994 E420, !991 300E and 1991 300E 4matic. All have over 100K miles. What is the best year for these models and what are the potential trouble areas. I am aware of the problems with the climate control and radio and the horsepower upgrades between model years. Being in an area that uses mag cloride on the roads how good is the rust proofing? How much would it cost to reseal valve covers and recondition a 400E engine. I like the simplicity of the inline six as I'm planning to do most of the maintenance myself. However, the Kelly blue book on the 400E is about the same as the 300E even though considerably more expensive when new. And the extra horsepower would be nice. I currently have a Q45 that makes over 300 horsepower. This would be my first Mercedes purchase since I bought my 280SE coupe over years ago.