Greetings. I am Adesh from Mauritius and I would like to get some walkthrough in upgrading the HiFi system in my 2015 BMW F30. The system comprises of 2 front speakers plus tweeters, 2 rear door speakers, one center speaker, 2 underseat subs and a 250W oem amplifier. I wanted to know how to hook an aftermarket dsp processor and a more powerful amp e.g. Pioneer GM9605 to the oem amp wire harness. A detailed explanation would be appreciated.