How exactly would I go about replacing the rears in a 91? I bought the correct size speaker, so that won't be an issue. Can I do all the work from the trunk, or will I need to take off the rear tray (and if so, how do I do that)? Thanks.
Well Nissan had the bright idea to make that rear shelf hard to get at. The way to do it is this.
1: Remove lower seat cushion by pulling tabs on the front lower portion of the seat where it meets the floor.
2: Unbolt rear seat cushion with 2 (12mm IIRC) bolts. Lift up on seat it will come off of the supports.
3: Unscrew the 3 big plastic screws, a coin works best to get them started then just use your finger to spin them like a record.
4: IIRC pull the rear shelf toward you. There are plastic connectors that hold the shelf to the metal. I think they need to come forward. I pulled my straight up and broke a couple of them now my shelf rattles.
5: 4 screws on top of speakers. They are top mount so you have to do them this way.
Its not that hard takes like 10 mins to have everything striped out. That rear shelf is what gives me trouble thats why mine are now broken. Look from under(in trunk) I think you can see the plastic holders they are white not the dark grey plastic screw thingys.