@FreeSoldja Ooh, I hadn't even thought of that. It's doable, but there may be some issues concerning the driver's position.
Sometime soon I'll take another crack at this mod and expand it further.

I would be interested in you doing it for ATVs. I think there was one already, but I can't find it anymore.

@Goliat Oof, that's a big one. Unfortunately that's just too big of a project for me to work on now but it might be something that I create in the future.
If you really want to add this to CUP vehicles, I recommend looking into how FFV seats are actually implemented into existing vanilla vehicles, and toy around with the code.

Hi @poly i trying to do it in vehicles from Cup Mods, but only for play with my friend. Certainly its very complicated

TLDR: It's complicated and annoying.

@Goliat It basically just replaces the front passenger seat with a gunner (firing-from-vehicle) seat. It's a bit complicated to do but it's possible. I highly recommend using Leopard20's Advanced Developer Tools to check the current seating setup of the vehicle you're trying to modify.
Speaking of - what vehicle are you trying to modify? I may make compats.

How can i do this in another vehicles?