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.
Ok. I have to agree with Phil on most of what he has said. I love the CL series pads because they give almost the same pedal feel when they are cold or hot. I use them on my race car, a 2500# car with 700+ HP, that is a circle track car, 8" tires and OEM single piston calipers.
I have found the Lotus to have too much front bias. Now my Exige has 308mm front and 288mm rears. I played with pad bias, swapping to dual piston rears and finally removing the ABS and booster. I have split masters with a balance bar setup. I run a custom setup to allow me to use Wilwood 4 piston calipers all the way around. Because of the calipers, I had to switch to CarboTech pads. XP10s started to fade at Watkins Glenn but ran fine on less high speed tracks. I have found XP10s not that great for street because they need some warmup time. I am going to try XP12s all the way around at Barber next week. I also picked up a set of AX6s to use on the street.
Now, I am a person who likes rear brake bias. If you have 288mm rotors all the way around, I would make sure I had the same calipers on all four corners. Start with CL6s on all four corners. If the car feels a little pushy on corner entry during braking, try a set of CL8s on the rear. If you are going to track the car much, I would not use CL5s. CL6s work great on the street but the will make a little bit of noise.
Also, I prefer full floating rotors with gas slots vs. drilled rotors. The slots will eat pads a little quicker but they do a better job of helping the pads disperse the gas build up and keep the pads cleaned up. With slots, I believe you have less of a chance of developing cracks from the drilled holes.
If you followed all of that then "Good Luck" and have fun. I see that you are located in NC, if you are in the Concord area, give me a shoot. You are welcome to come over and check out my setup.