Michelle:
Most of the folks on this forum work on their own cars or have an intrest in knowing what is involved with a repair. I think the first step you need to do is check your car for mechnical soundness and purchase the Mercedes-Benz W124 CD work shop manual to understand what is envolved with maintance and repair of your 1988 300-E.
this is a fairly simple design and can be maintained by its owner by purchasing a couple of tools and taking a weekend to look at the CD manual and become aquainted with the car.
The folks on this forum are really nice people and their are many approved Mercedes-Benz technical people who regularly respond to questions to help new owners of these 15 year old cars.
As far as the question to modifiy the 300-E my opinion a good perportion of the owners of these cars have been restoring what was stock to keep them running with the exception of shocks and wheels and tires. The biggest modification is the Hella or Bosch European headlights that in its self is a vast major improvement over the USA headlights and since you live back east you will appreciate the difference these lights gives you over the normal H-4 lights that were installed in these cars for the USA.

Best Regards
Bob Geco
Member of the Mercedes-Benz Club of America
Member of the Mustang club of America