Ok guys a couple things I have learned from installing a head unit. Remember that there are factory amps in the car. On the new radio that you get, there will be a (blue?) "power turn-on" wire. This is the wire that you will have to hook up to the following:
1) power antenna
2) amp turn on wire that goes to the car
3) any other amp that you have
Now, what I also suggest that you get is an inline dB reducer. This is becuase a new head unit is sending out an amplified signal to the amplifiers and it is getting double amplified. You can solve this by two ways.
1) Get a little unit that reduces the signal coming out of the head unit. Go to a local shop and ask them, they will know what you're talking about.
2) Buy your own amps and rewire the speakers to those amps. This way you can use the pre-outs (RCA) ((if your new head unit is so quipped, most are)) and hook those directly to an amp. The preouts are NOT amplified, so that is why you would have to send them to an amp.
Option #2 is obvious more money and more time consuming, so I suggest going with option #1.
When you get a wire harness, on the back of it, it should say 91-96 G20 or something like that...its basically a NISSAN harness. I would suggest going to Home Depot or any other electronics store and buying "Butt-end connectors" This is to put the two wire harnesses together. The one to the Car, and the one from the headunit. You can then use a lighter and hold it to the plastic from the "butt end connector" after you have crimped it down to shrink the plastic.
Another thing you will notice is that the G20 has TWO antennas...one in the back, and one in the winshield. They make an antenna adapter for this. You will need this antenna adapter. It goes from the (stock) two prong, to a (new) one prong. Unless you buy a head unit with the so-called "diversity antenna" thing...but ive never seen that.
Remember, dont use the cage thingie that comes with a new head unit. Use the two mounting brackets. They should say how to mount it to a nissan in the manual.
What I found on my Kenwood is that the brakets dont set the radio out "far-enough". What i mean by that is when you put the black console cover (the one with the two a/c vents and hazard switch) the radio wont stick out far enough to put the "little plastic athstetic plastic snap on piece" around the radio. So I had to buy 1/4 spacers and put those behind the screws when you screw the radio in. Then it will fit and make it look nice.
Note: IT may be different for your radio...who knows?
Hope that helps...
Ohh umm im not sure if pre 93.5 have stock amps...they may not...you should consult ur FSM
