This 1993 BMW E34 M5 from Europe is currently for sale out of Rochester, New York with an asking price of $16,500. The original engine has been replaced by a 5.5 L S70B56 V12 from a BMW 850CSi. The rest of the powertrain consists of a Getrag 560G six-speed manual transmission connected to a Quaife LSD. The swap was performed by Brett Anderson at Koala Motorsport in Cleveland, Ohio in 2008. The brakes have been upgraded to UUC Motorwerks four-piston brakes all around with 14″ rotors up front and 12.9″ in the rear. The suspension uses EDC III self-leveling shocks with HR springs and upgraded swap bars and strut brace. All of these modifications make for one of the most unique BMWs out there.
Source: Craigslist and Bring A Trailer via ESD reader Alvaro
Other than trying to build an unique car I don’t see it being worth it. After 1991 E34 M5 got 3.8 liter six with around 340 hp, 850CSi V12 had around 380 hp. Considering weight gains from heavy engine additional 40 hp don’t seem to be worth it. But maybe it’s just me.
I would think the torque curve would be vastly different.
The s70 is only 30lbs more than the s38.
The s38 is an iron block and the s70 is an aluminum block.