You sound just like the mechanically inclined it would take to own and maintain a 400e. Everything that was said above is pretty much right on. I own 2 400e's and if you love v-8's, like I do, they are a great ride. I think you have to try to buy this car cheaper though. Offer the guy $600, figure you'll go as high as $750, and if you can get it done for, then walk away. I can't imagine there will be anymore work maintaining a 400e than you no doubt have experienced with one of your "beamers".....and if I can be a "snide" Mercedes owner....probably less! Yes the wiring harness will need replaced. I've seen them on Ebay for $200-$500. There's a member of this website, Dave Hendy, that also has them for a good price. And finally, you'll have the wisdom of the PP Mercedes crowd to get you through most anything else. Probably what you've already experienced from the PP BMW members. Good luck. Let us know.