I bought this 92 BMW 525 touring to take its black interior and use it in another touring model I am fixing up. My original intent was to just send the chassis to the salvage yard when I am done taking what I need. The car drove so well on the way home, that I am offering it cheap to anyone that wants to build a 2013 Challenge car with it. It is not worth restoring IMO because both left and right floorboards are rusted out with some intrusion into the rocker panel on the right side. See the pics in my garage (mda185).
Here is the good: Very strong engine. ~130K miles. Runs smooth at highway speeds and makes good power for a 2.5 liter. No leaks or funny noises from the Vanos. Auto tranny still shifts well and does not slip. Suspension has not been refreshed in a while but it still rides, steers and handles well. Not race ready but a good set of springs and stiffer rear swaybar may be all you need. The wagon already comes with a 25mm front bar and that is same diameter as M5 touring bar. It has the self leveling hydraulic shocks in the back and they still work. Tires are still in very good condition. Doors are in fair to good condition with no rust at the bottom. Windows all work.
The bad: Floor is rusted out in two locations. Interior will be stripped. I will include a carpet you can use but not install it. I want to leave the rust damage open for inspection. I will definitely include front driver and passenger seats but no promises beyond that. Sunroof cassette will not be sold with the car. If you are making a racer out of this chassis, you will want to weld up that opening in the roof anyway. Engine does not idle well once warmed up. It is probably a combination of bad O2 sensor and/or vacuum leaks in some the rubber hoses under the intake manifold. Not hard to fix if you know these engines. Auto tranny leaks badly from selector shaft and possibly the drain pan gasket. I did not investigate further as I have no intention to use this car. Previous owner took the rear brake light and turn signal housings before I bought the car. Front headlights are installed but not hooked up. He had cut the wiring harness for Euro headlights that were removed prior to my purchase.
Here is the best part. I will sell a running, drivable chassis for $500.00 or best reasonable offer. That will leave plenty of room in your budget for other parts. Contact me at mda185 at geemail dot com if you are interested. I am located in central NJ.