If you paid so little for the car I'd say it is wise to invest 2-3K on it.
I did the same with my c280 97 (bought for much more in Brazil) and the outcome was great. I got a "brand new" 1997 car (about 40K miles) and added 2.5K dollars to the cost.
Mercedes are great cars and this kind of action pays for itself.
Jorge

PS: If you are good in doing it yourself things get even better.