[chris_flies]

Pads: I would recommend Porterfield R4's, but they don't have them in 135i fitment. I've heard great things about Hawk's DTC series, and they have different options for different performance needs.

Shims: People who do heavy tracking in the 135i all seem to have good results with Ti shims. The piston noses and dust boots have a tendency to just disintegrate from the heat. You may want to look into a different brake set-up for the front axle if you don't want to rebuild calipers every season...

Rotors: OEM rotors have aluminum hats, which gives a solid advantage in unsprung and rotational mass. That said, they also seem to have issues with warping. I've gotten good performance from my StopTech rotors, and I'd happily recommend them. Regardless, I'd buy from FCP Euro for lifetime replacements for the cost of shipping your used ones back to Connecticut.

Tires: I really loved my Firestone Firehawk Indy 500's. Truly loved them. Fantastic tread life, inexpensive, offered good grip with little temperature issues, and were comfortable and quiet driving to and from the track. They weren't the best in the wet, but it meant that wet track days were fun and made for good learning opportunities. I recently upgraded to Bridgestone Potenza RE-71R's, and, while they're much grippier, they aren't as much fun. They're snappy in their loss of grip regardless, they're noisy and harsh on the street, and they just aren't as playful on a nice rainy day.

Your car is very tastefully upgraded, and that setup will take you pretty far before having to do anything major like coilovers or an LSD. Enjoy it, get what you can out of it as a driver, then upgrade what you feel like you need to upgrade. I'd look into some Dinan camber plates; they'll fix most (if not all) of your outer edge wear issues and give you a lot more grip up front, which is desperately needed in these cars.