Kenwood basic m2

[Johnny25]

I'm not sure where to post these questions, but I hope this is a good starting point. I got this amplifier from my father, and since it is about 15 years old, I was just wondering how it compared to amplifiers today. For example, what is the sound quality comparison, and are amplifiers today really so much better? More importantly I would like to know what this E sensor is, it is shown in the attached picture. What could I use it for? Also, how would I go about wiring this amp for max power? Would I just bridge the channels? I think this is a really great amp, and it sounds very good, especially with the kenwood pre-amp that it came with. I don't mean to get off the subject, but while I have the chance to ask people who eclipse my knowledge of speakers and amps, why would a speaker have an rca plug acceptor in between the positive and negative wire connectors? I'm sorry about all of the questions. It is just that I have a real problem with not knowing answers to questions that really interest me. I don't want to lose any more sleep over them. Thanks for you help.