Yeah, first gear is trash. Most of us drag racer's have first gear disabled completely, which actually lends to a much nicer street driving experience.
This has all been covered ad nauseam.
https://www.supramkv.com/threads/bflash-announces-mg1-unlock-solution-tuning-your-2021-supra-is-finally-almost-here.13412/post-212944
Many many threads (that one included), that post, lots of research, investigation, etc has been done on this.
It's 100% a...
I mean, I know you say that, and they are expensive, but the margins for a high-quality part aren't exactly as high as you'd think. Obviously, I can only speak for EOSpeed manifolds, but they're all handmade by a one-person machine stop here in the Chicago area. The entire market for them is...
All modules must be available for the ECU and components to flash through ISTA. If something is missing (the factory amplifier) you will not be able to preform the brake recall.