Ran across this build on e46fanatics.com today. The guy is in Norway and started the build in 2008. According to him, taxes are astronomically high in Norway, such that a normal E46 M3 ends up costing north of $150K US. The taxes are based on the car's HP over a certain amount, like 170 or something. So most people drive low-powered vehicles. So he took a 318i sedan, and an M3 SMG coupe he got for relatively cheap from Germany, and married the two together.

And yes, the car is driven on the track regularly. The initial build was completed using mostly OEM parts, including M3 front fenders and rear quarter panels (fender flares molded into the rear doors). I believe the M3 front fenders were the only parts from the donor car that were cut. Everything else was either a straight swap, or bought new and modified (quarter panels, he didn't cut the M3 quarters). Guy said the M3 engine started up instantly on the first try after getting it into the sedan chassis, and ran perfectly. He used the complete M3 engine and body wiring harnesses so the electrical connections were all plug-n-play pretty much.

About a year after initial completion, on went the ESS supercharger. The guy reports hitting 310 kph on the autobahn (over 180 mph), so this car is no joke.

By far, one of the cleanest, most meticulous build I've ever seen, with extremely high attention to detail. Not to mention the choice of paint is absolutely stunning.

Probably take you a couple of hours to look through all of it, but trust me, it's worth it.

http://forum.e46fanatics.com/showthread.php?t=578901

A few videos (large files)
http://www.simracing.no/rudskogen_0001.wmv
http://www.simracing.no/vaalerbanen300809.wmv


Project car:


Donor:


M3 and 318 fenders merged together (M3 fender is longer and interfered with front doors):


M3 rear quarters going on - they cut the quarter that overlapped the door, then blended that part of the flare into the door itself:


Track wheels *drool*


With Michelin Porsche Cup slicks *more drool*


Color choice


Painted


M3 powerplant + KW V3 and StopTech 6-pot brakes installed


Underside completed. Every part was thoroughly cleaned, and many brand new parts were used, so it was like assembling a brand new car


M3 Interior going in:


Dem seats!!! Reclining Recaros!


Rear seats installed:


Fully completed:




At the track




OEM wheels + spacers for street use... sick!


Supercharger installed


Putting on track wheels with new 275/35-18 slicks




Artsy-fartsy engine shot


And the ubiquitous rolling shot