Cool. Well hope my answer helped... RC6 or a DTC60 or a Ferodo 3000, etc on all 4 and then you can tune to your liking... When you tune, it will likely be to increase rear bite...For disclosure, I've got several years on track experience with M3s across two generations, and run bmwcca advanced group. I'm getting into a Lotus for the first time, and it's one that Phil built, so it's got some power, but I believe the brakes are stock. In my experience with other track forum sections from other makes there are usually a few 'known good' combos of pads or pad/rotor upgrades on the market, so I was just looking for some experience. Saying "it depends", while of course it does, isn't terrifically helpful to someone new to the platform.
I've had a few M3s. They're the hardest to loop car on the planet. Pure glory and the engineers of the 36 and 46 deserve a special place in church! The Lotus is a super easy car to drive fast once you learn how... it's like a Porsche. If you're like many, the M3 allowed you to build habbits that work fine on that car but will make you a spin doctor on the Lotus. Additional rear brake bias will make that more of an issue. My suggestion is stick to same pads on all 4 corners until you really master it, and even then you might be happy to keep it that way...