Id say none, my first mini clubman est had 4 classic Lucas spotlights, and my second one and square 8's built into the grill, much like the one porche posted, they really looked the part, chrome spots in a polished grill, but your mini looks just right as it is, mabie it just needs a small lotus badge on the grill
There's got to be some literature out there somewhere. It's was done "back in the day". Probably Ford crank with mini output shaft + gear box to sump adapter= cool cool car.
Can lay my hands on lotus lump .... but
Old engine now , parts a chew on , reliability always been an issue and power not all that great ( good torque tho) ... can do so much more with a series nowadays ( I ran an a series turbo with 171 bhp) about 10 years ago
16v heads , supercharging , old school Weber’s etc ... all great options