3 door dash is different to the 88-90 spec dash
which is different to the 90-91 dash
which is different to the 92 spec dash
pre 90 spec and post 90 spec are fairly different but you can swap them over

you will need to have everything, and i mean everything from the 90 spec car to transfer over, inculding heater controls, switches (which will be a problem as the looms are different) indicators (and wires and stuff) as well as the ecu brackets, the kick panels, even the centre consoles bolt up in a different place

you will also need to be a be "creative" when it comes to placing the aws stuff as well, but it's not difficult, just time consuming getting everything to line up properly