Good evening, I’ve been the owner of an E39 BMW for 3 weeks. The BMW cassette radio was built to provide a very miserable sound. Therefore I bought a Kenwood radio which fits with a suitable BMW adapter cable. The sound was better but I’m still not really satisfied despite some games at the settings. Now I came across the company I-Sotec offers the plug & play capable power amplifiers which should fit with a suitable adapter cable in every car and to do so s I have to say that I don’t have any idea about Car Hifi but I don’t want a bass cave either. It’s only important to me to get the best possible out of the speakers without having to tinker on the car and without having any boxes in the interior or trunk. Such a current I-Sotec power amplifier costs incl. matching adapter about 400€, . The thing offers: Quotation: Reinforcement front + subwoofer 2 x 90 + 220 watts music at 4 ohms power 360 watts music at 4 ohm channels 4 / 3 (Front + Sub) Reinforcement Front + Rear 4x 90 Watt Music at 4 Ohm The values don’t tell me anything, so the question arises if this makes sense at all when I have installed original loudspeakers from BMW? It should be the normal stereo system. Otherwise I often hit amplifiers in the bay with the following values which cost up to 50€: Quote: 4 x 65 Watt at 4 Ohm (4-channel operation) or 2 x 65 Watt + 1 x 100 Watt at 4 Ohm (3-channel operation) In addition the adapter cable which has to be connected somehow. Since I have already installed an ISO on BMW adapter for the Kenwood Radio, the question arises to me, where should this adapter then go? Does the adapter only loop the signal so to speak or does the Isotec adapter cable have a branching off for the radio? On the photo I unfortunately don’t recognize that. Otherwise, 2 jack connections are free on the radio if I’m not mistaken. What do you think? Does the whole thing make sense at all or does my project creep up d the speaker doesn’t make any sense?