dtrain
A couple thoughts on the 230SL. It can indeed be a fun project and a great car to drive. Depending on what "in pieces" means, this car could be a simple rebuild or it could be a project that will consume a considerable amount of your time and money. That said, my first inclination is to say, RUN don't walk away from this car unless you are a good mechanic and/or have deep pockets. This is not a car to use to learn auto mechanics. Most of the time you can buy a car that is in good condition for less than what it costs to "restore" one and be driving a lot sooner. If you buy a driver, you can spend your time and money on the little fun things that will make the car more personal for you, and enjoy driving the car at the same time.
In addition to the things that have been mentioned as potential problems, the fuel delivery system can be a real pain in the rear and a real drain on the pocketbook. If the car has been idle for some time and the fuel has been allowed to evaporate any or all of the parts of the fuel system may be (probably will be) siezed up and require a thorough cleaning and/or a rebuild. This may include the fuel pump, fuel injection pump, injectors, cold start mechanism and other related parts.
Again, if you are mechanically inclined and all the parts are there and are in reasonably good condition this may be a good deal. If, however, you are a novice you may want to choose a simpler project to learn on.
Good luck
Iverson