qualities of a great bass amp?

This is for a car amp. I have some amps from the late 80's. they supposedly have very good power supplies. This amp was sold in two configurations. HCCA250, high continuous current amp. This amp was rated at;
2 x 50W at 4 ohms
2 x 100W at 2 ohms
2 x 200W at 1 ohm
2 x 400W at 1/2 ohm
1 x 400W at 2 ohm bridge
1 x 800W at 1 ohm bridge

In the other version 2150GX is the high voltage version and was rated at;
2 x 150W at 4 ohms
2 x 300W at 2 ohms
1 x 600W at 4 ohm bridge

The amp I have is the high voltage version, but is fairly easily converted to the high current version or something in between.

From what I have inferred (guessed, made up, imagined) from extensive reading the high voltage version is better at the higher bass and the high current is better (legendary) at lower bass. In my particular application I would want this amp to control a 4 ohm woofer from 80 to 35 Hz or so. I am looking for sound quality only. I don't play my music very loud.

Thank you for your time. I appreciate greatly anything you can tell me. Car audio is filled with urban legend and it is very difficult to get unbiased information.