Amplifiers and better speakers. But amplifiers are a must.
Setting the bass boost on your car's amp can be an easy way to increase the "bump" in your car whether the amp is running your speakers or subs. i wouldn't increase it too much for your speakers, i would let the subs do most of if not all the work of the lows (thats what they are built for). i would first adjust the sub level and low level on your stereo first if more bass is wanted, turn the bass boost knob or control on your amp no more than 3/4 the way up. again if more bass is still needed an new better amp or bigger better subs may be the answer.
The bigger your car, the more coolant you need to put in. The bigger your engine and car, the more coolant you need
Depends how much bass you have. A stock soundsystem probably about 2 feet. If you put an aftermarket subwoofer, then maybe 10-50 ft. It all depends how much bass you put. Some competion level cars you can hear from half a mile.
all you need to sell your car is your car title
It all depends on the actual car itself and how you take care of your car. I recommend that you refer to your service manual for more details.
One can purchase car bass speaker systems from many websites online. The most popular websites to purchase car bass speaker systems are BestBuy, Overstock, and Amazon.
It varies from car to car, need more info.
not all car washes need insurance
what car wouldN'T need more maintenance should be the question
Yes.
You can go to insurance.ca.gov. There you will be able to learn about all the California car insurance laws that you will need to know.
The JBL MRX518S 18" Bass Reflex Subwoofers are the best.