It’s not being engineered from the ground-up; these are all common modifications in the car guy world. The only semi-complex part will be getting the suspension custom-valved if there’s not something already available on the market for daily driving, and even that is fairly doable.

Adapting comfortable seats is a straightforward process; adding noise dampening and carpet is a straightforward process (good noise dampening material can turn almost any rattle box into something really close to if not equal to a Lexus in terms of noise). Exhausts are not voodoo, resonators and mufflers are available for virtually any conceivable application… etc

What I would wish them good luck with is not running out of steam to get it to where they want it.