I know that I need the front piece that holds the radio, but is there a rack of some kind in this area to support the radio. Thanks, BA

 

You need these to mount the radio into the dash.

http://www.ebay.com/itm/200455885746?redirect=mobile


These brackets screw into the sides of the radio/head unit and then also into the tray/cupholder below it (or not, if you're going with a double-DIN aftermarket unit). Then that whole "cluster" mounts inside the dash via the brackets.

That listing says that it fits all 89-94 Maximas but I can tell you from experience the 89-91 brackets and the 92-94 brackets are different. The 89-91 sits deeper in the dash.

 

To give you a better understanding, here's the unit from one of my 3rd gens. Notice how the brackets tie the radio and cupholder/tray unit together. Then this is all screwed into the dash via the same brackets:

 

the ebay link and james pictures both show the 92-94 bracket

youll want the 89-91 bracket which looks like this, it has slightly different cutouts

 

Good to know that I can get this part on eBay, I will keep the link.

 

Remember though, like we said, they are different 89-91 and 92-94. The one in the link is 92-94 and therefore won't work on your car FYI