Mustang two seat conversions

[BarnOwlLover]

Many of the P-51s flying today were converted into two seaters, and even the only currently flying P-51H is a two seater. This seems to be able to be done with little if any modification to the airframe aside from removing the fuselage fuel tank. But what else has to be done to convert a single seat P-51 into a two seater? I also know that most of them have the head/shoulder armor removed from the seat at least, but what else has to be changed or converted?

 

[N4521U]

Add the seat? Sorry.
There is a spreader bar at the back of the pilot seat. Keep the sides from collapsing.
No stick, no instruments, just the purr of 12 cylinders in stereo!