I got the E9x M3 hood dampers from my local BMW dealership parts counter. 90+% of all my BMW parts I get from them. I've purchased so much from them that the parts manager & I became good friends and he hooks me up.
If you didn't want to go that route I'd be surprised if ECS didn't have them.
I believe the 135 stock hood weighs something like 47lbs and the E9x M3 hood is aluminum and weighs only 20-some pounds. So the dampers would be rated accordingly.
Watkins Glen, Summit Point (Main) and NJMP I get close to that (just shy).
I do not have any data yet on oil temps with the ER Comp twin oil coolers as they were installed with this latest round of mods, but I have high expectations that the twin high capacity coolers will greatly reduce my oil temps, because the I couldn't even finish a 30 minute track stint with the stock oil cooler due to high oil temps.
My track seats are Sparco Pro2000 seats with Sparco seat mounts for the 135. The seat with slider rails and mounts weigh ~15 pounds each. They are fixed back. Yes, they will have to be coded in (chime coded out). Check out NTX Coding, they can hook you up.