103 injector replacement--worth it?

[Joe Bauers]

I have a 1989 300SE with 123,000 miles that runs well. Would it be worth it to change the injectors? My only complaint about the car is poor fuel economy, which my MB mechanic friend says is to be expected, given the weight of the vehicle. He doubts that new injectors would add much in the way of either performance or economy. If I did decide to do it, I would handle the job myself, so there would be no labor cost involved.

Anyone here have experience with this? Your opinions would be appreciated.

Joe B.