HUGE list of stuff in the link
This E46 wagon popped up for sale on Craigslist in Denver, Colorado six days ago. It started out as a 2001 325iX, but has since been heavily modified into the beast you see here. The S54 straight-six engine, sourced from a 2004 M3, was rebuilt with new valves, valve springs, valve guides, rod bearings, and a new VANOS solenoid control unit. In order to get power to all four wheels, an oil pan and a six-speed manual transmission from a 330iX were modified and attached to the engine. Shorter differential ratios from an X3 are used at either end.
On the outside you'll find an M3 front bumper, widened fenders, upgraded brakes, and a set of Apex FL-5 wheels wrapped in Michelin Pilot Super Sport tires. Strangely, it looks as if the rear bumper has been left stock, which makes the rear end look a bit odd compared to the rest of the exterior. Still, everything incredibly well-done, almost as if it came from the factory.