Sequential - I am not yet sure how to emulate damage for that. If someone with a good understanding of gearbox mechanics reaches out to me and will give me advice on how, I will look into it.
Note that does not mean nothing is done for sequential - it is quite the opposite. For sequential, bunch of things are implemented:
* Overrev protection
* Block neutral until car stops
* Refuse shift based on engine torque - this is particularly big one, and here's why. Many older series had sequential gearboxes with no auto lift/throttle cut. If you watch FIA GT 2003/2004 drivers lift and or clutch on downshift. Same with Supertouring. And plugin tries to emulate that, even though it is simple tricks and I need inputs from the more knowledgeble people, it is a huge step forward in immersion in my view.
https://www.youtube.com/watch?v=PK8eRM4Uqm0&t=5s
So short answer, not yet - but if I will ever get good inputs from physics/mechanics experts, I will add it.
I could potentially calculate by how much requested shift exceeds the set torque, count that as damage, and kill the box eventually - but not sure yet. For H-shifted it works nicely - you can say, kill gear 3 and you'll have to finish race without gear 3- but for sequential.... I am open to suggestions.