Matter of opinion. I'm a Kicker/Rockford Fosgate/JL Audio fan. Alpine is still pretty good too. Stay away from brands like Dual, MTX, Audiobahn, Sony, and pretty much anything else with a 'too good to be true' price tag.
Digital Designs Z series amps are the best brand because it can go into go into any car audio forum and has an authentic sound.
The Kicker ZX300.1 Subwoofer Car Amplifier is great.
Sony has the best car amplifier on the market. These are typically more expensive as well.
Depending on who you believe - this one was said to be best Krell KAV400xi 200Watts
The cost of car amplifiers is going to vary based on a number of things such as the brand, the car it will be going in, and what amplifier level is needed.
Behringer Europower EPQ2000 Power Amplifier is one of the best power amplifier that has high-quality components and ensures long life. It has several features and variable controls.
This is not a very good amp, a better brand is recommended.
You can mount your car amplifier in the back floor or in the trunk.
There is a good location for your amplifier to be installed inside of a car. The best location is inside of your trunk. If you have a SUV, such as a Nissan Pathfinder, you would install it on the back of a seat. If you have a Sedan, such as a BMW, you would install it on the very back of the trunk.
It depends on your car, but for a large car you can get a proper subwoofer with a wooden casing for less vibration.