Sound like your best bet is to remove the pocket and mount the empeg there.

i remember the trick where you can mount the cadge behind the facia and if you take the wiring loom off the back of the sled and refit from the inside , you should gain enough depth so that it will still fit ok.

Any spare skyline bits especialy dash trims are going to be rare, in the uk you have no chance what so ever of finding a skyline at a breakers and if you did not with any useable parts left.

My mate has the R32 GTS? (2.5 NA RWD), nice cars.

C.