Anything you do like shimming the seat mount to gain height will decrease its stability in a crash, the best thing, especially since raising it up will practically make the headrest hit the rollbar is to get a cushion for the seat to get you up a little higher.
I used a T40 on my 1997 Wrangler on the forward brackets of the fold-and-tumble rear seat.
If there is a seat and a seat belt, yes.
Under the passenger seat.
Yes, that should work.
Yes, they should be the same
To remove the seat in a 2013 Jeep Wrangler, first, slide the seat all the way forward to access the rear bolts. Use a socket wrench to remove the bolts securing the rear of the seat, then slide the seat back to access and remove the front bolts. After all bolts are removed, carefully lift the seat out of the vehicle. Make sure to disconnect any wiring for power seats or sensors before fully removing the seat.
If it has a passenger air bag I wouldn't......
under the passager seat.
under the front seat.
Under the passengers seat.
There are several different ways to add and change seating in the Jeep Wrangler and the Unlimited and the seats can go into the other vehicles. You can use the back seat of the Wrangler to go in a third row of a Wrangler Unlimited though the mounting brackets sold aftermarket from a company that are not NHSTA tested. There is a business called Little Passenger Seats that makes seats for the Jeep Wrangler Unlimited that will also work for the Wrangler and they have safety tested their product and passes NHSTA regs. The problem with adding and switching these seats on your own are finding and mounting seat belts. That is why Little Passenger Seats is great because the brackets are included and seatbelts come mounted on the seat. Check it out.
If the seat is wore down you can put more padding in the seat or make sure the springs are functioning properly. Easiest way just sit on a pillow with a seat cover over it.