My 93 3000gt is just a fun car to cruise around with. It's not perfect and I don't expect it to ever be. It has high mileage and had a quarter panel replaced 10+ years ago due to a minor fender bender. It's the kind of car I'll still take out when there is a chance of rain, or I'll drive to work and park in our tight parking lot. None of this means that the car is a beater. When I have a chance to do something to make the car look/perform/handle better I'm going to do it and go about it with the "bang for the buck" approach. Now the stereo system is the perfect example of this.
After 25 years the oem speakers have seen better days. I couldn't turn the volume up past 50% or I'd heat an obnoxious scratching/buzzing sound coming from the passenger door. I thought about trying to find a used oem speaker, but after inspecting mine I realized they all were deteriorating. I figured any other used oem speaker I found wouldn't have a lot of life left either. Here's a photo showing how bad the fronts were. The rear were in a lot better shape, but I decided to replace them anyways for peace of mind.
I ordered "Rockford Fosgate Prime R165-S" component speakers for the front and "Rockford Fosgate Prime R169x2" speakers for the rear from Crutchfield. I like Crutchfield because they are really good at showing speakers by vehicle. Meaning I was not worried about physical fitment with these RF speakers. It's not always the diameter of the speaker you need to worry about. The speaker depth is important. If you go with a speaker that is too deep it could hit the front windows when you roll them down. If you get 3 way speakers that have the built in tweeter in the middle... Sometimes the tweeter can stick out too far and can interfere with the door cards. Crutchfield is good at listing dimensions and they also will include install kits/wiring adaptors for free. The total cost from them after shipping was $114.98
The fronts RF speakers have their own tweeter, but they do not utilize a crossover box. The rears are a 2 way speaker just like OEM. A lot of 6x9's are actually 3 way, but I wanted to simulate what came with the car. Both sets of speakers are 4 ohm just like the originals, and their power level at RMS is lower than most aftermarket speakers. On the back of the stock speakers it says "15W". Now it's not clear if that's RMS power or perhaps the minimum Watts for the speaker to operate. Quite a few aftermarket speakers operate at 80-100W RMS. These RF speakers are 40W RMS and start operating at only 2W.
Everything came 2 days later. The rear speakers fit perfectly. I had to use the screws that came with the new speakers vs the original OEM screws as the heads were too big.
The front door speakers required a little bit of work. Now Crutchfield did send some plastic speaker adapters. The idea being I mount the speakers to the adaptor and then screw the adaptor onto the door panel. I opted not to use the adaptors. The speaker mounting points were oriented the same way, just they were slightly closer to the center than OEM. I ended up drilling 4 new holes just inside of the oem screw holes in the factory plastic speaker shroud. Then I screwed them in. Crutchfield sent wiring pigtails for both the front and rear speakers. Basically one end plugs into the speaker and the other end plugs into the oem pigtail.
Up to this point everything has been pretty much plug and play. The tweeters thought required some extra attention. I expected this. My plan was to retrofit the aftermarket tweeter inside the oem housing. Here is how the back of a 91-93 3000gt tweeter looks. In 94+ they changed the tweeter design. You could still probably retrofit one in the later style, just not as easily.
First you need to take apart the tweeter. The grill can be removed by gently straightening out the bent tabs on the back. Then there is a Phillips screw for the wiring board and a larger Phillips screw to remove the tweeter from the plastic housing. The oem wiring goes on each side of the plastic housing so to remove it you'll need to snip one of the wires. It should look like this afterwards:
Now the RF tweeter is smaller in diameter than the factory one, so I had to make a plastic washer adapter. I used an old truck mud flap. The outside of the washer needed to be the same diameter as the stock tweeter and the inside needed to be the diameter of the aftermarket tweeter. I used a 2 3/4" hole saw to cut the outside diameter. It was a little bit too big so I carefully rotated it around my belt sander to file it down. You want it to fit perfectly inside the oem tweeter housing. If it's slightly too big and you try to press it into the factory housing, you are going to break it. You want it to slide in effortlessly. For the inner diameter I used a smaller hole saw. Again it wasn't perfect. I had to slowly enlarge the hole with a Dremel until the RF tweeter fit snug.
Here we have the oem tweeter housing, the RF tweeter, and the washer I made.
I used a hot glue gun to secure the washer in place. I glued it from the bottom. Test fit the tweeter and the oem speaker grill before gluing it. The washer can't be flush with the top. You need to leave some space so he dome of the tweeter doesn't hit the oem grill. You can see in my picture the washer is actually sunk in about 3/16".
Then you can install the tweeter and dome cover. This picture shows it in a few different states. Top left is with the grill cover off. Bottom left is just the grill cover. Top right is with the grill cover installed. Now the bottom right is actually a 94+ grill cover. I actually had some 94 oem tweeters I examined before trying to use the 91-93 style. It does show the differences though. The 94 cover has a wide outer ring and it has a plastic support cross underneath the grill mesh.
Now I ended up re-using the factory board with the male connector prongs. I de-soldered he factory wiring and soldered my RF tweeter wiring to it. This way I can plug the tweeter into the factory harness connector.
Overall I am very happy with these speakers. I can crank the volume up much higher now and the speakers sound great. I'm still rocking the factory head unit too. So everything looks factory from the inside. The 93 has the rare Clarion Head unit from the factory. It has the Aux input on the front. If my car was not a 93 I would have probably swapped out my HU for something different.