When it comes to running wires down your vehicle in-between other wires especially along larger power wires, you run the risk of introducing Electro Magnetic Interference or EMI. This has been known for years and shops, to this day, try to use speed wire in an attempt to save time and money. It was not until we called them out for the "cheap" practices that they started to twist signal wires but continue to use silicone jacketed wire, and copper tined aluminum wire that is not true OFC. That attracts static. Shock-wire is the only true quality wire that blocks EMI and is 100% copper in the 12v industry.
One of the many advantages of being our customer is that you dont just get the best of all worlds. Because we develop our product in house and test on all the vehicles meaning, we know the answer to your questions, First hand.
The Wavtech BassRESTOR is best discribed as an all in one solution for both repaiering and adding bass in situations where the factory system does not have bass or where the bass is rolled off to protect the factory speakers from damage at high volumes.
High level : AKA Speaker level is an amp that can handle an input voltage of 8-40v. This high output is common in factory amplified vehicles or where the
max voltage of a head unit is more then 10v. This is normally identified by a pigtail connection point or via the RCA on the amplifier (must check user manual to verify.) Some amps have a switch for this. NOT all amps have this future.
Low Level : is 0-8v of signal voltage. This is most commonly found inaftermarket head units. or other aftermarket units that use can-bus. Most passive LOC units output 0-5v so they are considered a low level and are normally RCA to RCA. Modern day ACTIVE LOC units can output 0-10v of signal.
In conclusion an LOC works as an in line filter that lest you control the signal, its intercity and in some cases the playable frequency range.
If your amp takes a high level and it is within the vehicles factory output range then you dont need an loc unit and can wire in and out of your amp
directly. In some fords the signal can be flattened at the OB2 furthering the simplification of the installation.