I would absolutely buy a metal guibo and I'm sure anyone else with a track-oriented car would too. I almost bought a 1M/BMW guibo but due to the failures I held off, don't know if it's still available. I know IRP makes metal/poly gibes for literally every BMW but the N54, including the e9x M3. I dont know which I'd prefer most between solid metal, bigger rubber, or something in between. Personally I dont care if theres some NVH increase, i think the benefits outweigh the negatives there.
I also agree about a rear seat delete, though I know NRW is working on a carbon one eventually. Personally I dont need full carbon, anything from plastic to sheet metal would be fine for me because you're still dropping 40+ pounds when removing the rear seat. Lots of "little" stuff like that would be awesome to see and have a quick turnaround development wise I think, even though as mentioned before I put my initial list in order of what I want. However I'd already have bought things like a metal guibo in a heartbeat if I knew I didnt have to worry about a failure from something random.