In Australia, seats must be mod plated (conform to Australia Design Rules). Be really careful when fitting different rails to different seats, like Datsun rails to Toyota seats. Reportedly, Engineers have said it is very difficult to get them mod plated, which all aftermarket seats have to be. You really need to spend some extra coin and at least get an engineer to design your fabrication. Then have th4 engineer do the work, or you can do the work and have the engineer to mod plate it for you.