I've got an amplifier installed already. I can crank it up to probably what equates to 7/8 volume without any clipping or distortion, but if I play with the dedicated bass know (or the factory bass slider in the eq for that matter) the 3.5s just can't handle it and sound like a wet fart.
I didn't realize you had the head unit with an EQ.- some of them are pretty nice, and very sought after as well. It's a great feature but still leaves you low on voltage so you'll need line drivers or an amp to be remotely loud without sounding like wet farts.
You have an amp for your mids and tweets? I assumed the one mentioned was for the sub... The Delco simply doesn't have the juice to push good speakers, and bad speakers perform poorly at all volumes. An amp will digitally process and filter the signal, making it exponentially better and you'll hear the difference in clarity- they aren't just for volume.
The speakers absolutely need crossovers, so you're on the right track there. They're necessary even when using an actual parametric equalizer or your basic equalizer like the head unit has, and even if you upgrade to high end speakers. By not sending speakers any signals they can't reproduce they don't distort and blow unless abused. The factory eq sliders don't even come close to performing that job and Parts Express has high, low, and band-pass crossovers that work perfectly.
If interested, the Soundstream amp is about $125 on Amazon and they have smaller versions for less money. They're similar to Pioneer to me- they're entry level, Wal Mart carries both brands, and I've had a nearly 100% success rate with both.
https://www.amazon.com/Soundstream-ST4-1200D-Stealth-Channel-Amplifier/dp/B01N9VGQRA/?tag=gbody-20
When upgrading speakers I can't recommend NVX enough. The quality and pricing is just fantastic and the only drawback is the speaker sensitivity is a tad low, but it's a moot point with an amp. There's also Dayton, Memphis, Skar, and CT Sounds in this price/performance range. Avoid DS18 as they're just a company who slaps a logo onto thousands of different cheaply made products.
For 3.5" :
https://nvx.com/search?q=3.5*&type=article,page,product I have the "N" series in my truck and am quite happy. A nice alternative is the Dayton 4" which I can also personally recommend and they should fit the dash just fine.
https://www.parts-express.com/search They come from Parts Express, another fine company with excellent products at discounted prices. They have ridiculously cheap sales all the time and I sometimes receive discount codes on top of that.
For 6x9" the NVX start at $80 and go up since they're sold out of their cheapest version.
https://nvx.com/search?q=6x9*&type=article,page,product My Cutlass is receiving the 150 watt components for the rear.
And the 6.5":
https://nvx.com/search?q=6.5*&type=article,page,product My truck has the 6.5" components- I love them.
A component setup will always sound better than a coaxial speaker. The component kits come with two woofers, two tweeters, and a crossover for both.
High frequency sound waves are directional, low frequency is not. That means tweeters need to be aimed. Mids should be aimed too but it's very slightly less important. Subs can be rearranged until it sounds best which is often not facing forward.
Kick panel speakers sound better than ones in the door which point at your legs and you'll hear vocals much more clearly. Put tweeters in the upper corners of the windshield or A pillar and aim to the opposite seat. Shoot rear tweeters straight forward.