strokd_86stang

im switching the interior in my 86 stang over to 87-93 and am needing a little help here..never done interior swap before!! i have a 87 donor car..i know the top mounting brackets don't line up..anything else i should watch out for?? another question..im not much on wiring, the wires going through the firewall on the 87 that is attached to the dash harness where do they go?? i know my 86 harness unplugged from the harness that goes through the firewall on the driver side...do i need to take the 86 harness out that goes through the driver side firewall and use the 87??? any help is appreciated