The Most Tenacious Mini Engine Transplant You've Ever Seen! The British auto specialist company Powerflex, took four long years to pull off this conversion. Installing a BMW S65 (M3) engine into a little R56 Mini Cooper S is no small feat! The car is ultimately destined for the track, as evidenced by the custom roll cage, dual clutch gearbox, and complete reworking of everything needed for this massive V8 engine to fit where a transverse 4 cylinder used to reside. I know I'd love to take this revamped Mini out for a spin! Congrats, Powerflex, and all of your dedicated builders.