Fair enough, I'l try that out with one thats worth my time to do it. This current one is my 3rd and its a literal shit box (rusted floors, jury rigged fuel tank, etc.) and its only a parts car for my next clean body. I just figured i would play around butchering this one, expect some more crazy stuff to be done to this one.Yes, 4" speakers are much better than virtually any 3 1/2" speaker, no matter how much they cost. And I agree with Seamus, I did a similar mod decades ago and cut out most of the metal behind the grills. But the OEM plastic mounts performed a crucial function that you didn't duplicate when mounting the 4's. You must isolate the front of the speaker from the back or the bass will virtually cancel out. So seal all the way around the speakers so there's no air leakage around the edges. Otherwise, the 4's will put out less apparent bass than even the POS 3 1/2's did.
I used component speakers in front and the sound is spectacular. 4's in the dash, 1" tweeters mounted on the mirror trim panels on the top front of each door and the crossovers stuffed under the dash wherever they'd fit. Getting the tweeter wiring into each door through the flexible boot was a bit of a chore though. The front speaker amp is stuffed under the passenger seat.
The OEM rears were 5x7 Toyota footballs as they were called. I tried a few different ones and they all sounded universally awful. I made adapter plates that bolt to the factory mounts for 5 1/4's and only used the mid bass from component speakers without the crossovers or tweeters. It really sounds better without having tweeters in the back than it did with them. They definitely add rear fill and provide a bit of surround effect. But it sounds like the band is on the hood instead of in the car which is how it should be
I made a sub box that fits tight up against the seat backs that's carpeted to match the OEM interior. Even with the hatch open, only somebody that really knows these cars would notice the box wasn't an original part of the car. It has 4x6 1/2" very high quality subs mounted facing downward in individual compartments. The box has 6 approximately 1 1/4" legs to space it up off the floor. The sub amp and rear speaker amp are mounted on the front side of the box and if you knew to look down through the small gap between the seat backs and the cargo cover, you might see them. This is all connected with quick disconnects for easy removal if necessary. But that sucker weighs about 90 pounds and removing it is easier with a helper. At one time I did have similar but slightly deeper box that held 2x10's that also sounded terrific. But the few extra inches of space it took up made the remaining space hard to fit groceries, etc into.
I designed, built and installed all of this stuff not long after buying the car new. Other than finally updating to a modern head unit a few years ago, it's all worked perfectly since '85.
And yes, besides enjoying the music, I equally like the music from under the hood.
1" tweeters mounted on the mirror trim panels on the top front of each door