Hello everyone! I own a 2016 488 GTB (LOVE this car!!) that has the JBL Audio system in it. For Christmas this year, I was given a subwoofer from Scuderia Audio. I decided to go ahead and purchase some nice Vocal woofers and tweeters and the JL vx400i amp. Everything seemed pretty straight forward, I took the left and right woofer outputs from the factory amp and used them for the inputs to the aftermarket amp. JL says that the vx400 can take 16 vrms on the input and the factory JBL amp only outputs 5.9 vrms on those circuits. Pretty simple right? Nope! Apparently Ferrari does a self check of sorts at power on and if it does not see the correct resistance of the factory speakers, it shuts the circuit off. This took a little to figure out as it was 5.9 vrms prior to disconnecting and 0.21v after install. We ended up hooking up a factory speaker back up and powering down and then back up and then that speak (only) started working. I was wondering if anyone here has experience in upgrading the audio in the 488 that already has the JBL factory amp. Or a diagram of the input harness from the infotainment system would be fantastic! I know I can ‘T’ into the factory woofer signal for the input to the new amp and have that power my sub, but I would really like to use my new speakers and have the new amp power those as well. I really don’t know a ton about audio and unfortunately there was no one remotely near by that I could take my car to to have it professionally installed. Positive note is I now know how the interior of my car comes apart . Any help would be greatly appreciated!!