Fried my first amp ever last week. It was on the 2018 with Harman Karden premium sound. Never had this problem on any BMW in 6 years. The technician that fixed it said he wasnt sure if it was a new design for the 18's or if it was HK. Either way, I recently bought a soak shield and will be tearing the trunk apart on these in the future. The amp is on the left side like most other cars. The cost of the repair was close to $2000. Sorry I couldnt post sooner..Hope nobody else has fried one!