I am retrofitting my 1965 mustang with an original am radio, plugged all the holes in the doors. I went with a Bluetooth speaker system. Two JBL Charge 4 - Waterproof Portable Bluetooth Speakers each set just in front of the seats on some mounts I made, and wired to USB ports I added to charge them. I use my phone to play through them and they are loud enough to hear on the freeway with the widows down.

You can get more for your money with smaller audio companies. But since you noted someone else is doing the installation, you may not want to spend the time on the research.

Those Alpines are good, but I think they are expensive.

Your money might be better spent installing a subwoofer first, but there is the issue of finding space.

When I was young I poured money into car audio. It's really wasteful, and some nigger will just steal it, but I understand. That said, I always liked alpine stuff.

Once installed please be sure to test your system from the outside.

There is nothing more ghetto then a car with a loud system but when they are driving by all you here is loose metal or the license plate rattling.

Alpine is still a good brand for car audio, not to tier but still money well spent

Pioneer is still ok as well and so is kicker but stay away as far as you can from boss

Recoil audio makes great door speakers and they're us made out of Arizona. I bought a set to try amazing quality. If going to add amp I would use a lci line converter unless you have swapped stock radio for aftermarket. Lci has one that will bypass factory bass cut filters and give full audio signals

https://www.crutchfield.com/p_108K603CF/Infinity-Kappa-603CF.html

These will get louder as the are more sensitive.

Alpine is great no doubt, but my ears like the infinity products and is what I put in my vehicle. In addition to having a pretty flat curve, having lower ohms and greater sensitivity will make it louder to boot.

And as always, Your mileage will vary and see your doctor before starting exercise.