I am not trying to knock you, and I applaud you for doing research on the forum, but with such a low budget, one has to wonder if you truly know what it takes to maintain these cars, especially one with 60K+ that will need a double wrench service.
Oil changes are ~$100 if you do them yourself, more from shops. Brakes are not cheap and neither is anything else you do. God forbid something should happen to the supercharger, Mercedes wants damn near as much as you are willing to pay for the car for a new one (I realize you can buy a reman or have yours done, but still).
As I said, my intent it not to belittle you, but you make sure you are aware what kind of expenses could be around the corner
Hell, to properly keep up an NA with the mods and correct maintenance, it is fairly expensive....