I want to install audiophile grade 3-way 6.5" speakers in my 2015 BMW 528i (F10), but I'm unable to figure out a fitment solution due to the fact that BMW uses stock 4" 2-way speakers (NOTE: my car is equipped with the stock audio system, and does not have the upgraded Harman Kardon or B&O audio). My local shop recommended building a custom fiberglass door panel, but I was wondering if there are any other options without resorting to custom built door panels to accommodate the speakers. Has anyone else had any luck installing a 6.5" 3-way audio system in a BMW? If so, I would appreciate any information regarding your experience. NOTE: The speakers I want to use are Focal K2 Power 165KRX3 (front). The specs are on the manufactures website here: http://www.focal-america.com/product/165-krx3/
Hardly a sound expert, but I'm sure the more you want to do & the more that involves custom fabrication, the more expensive it gets. I don't know know about speaker size details, but you might want to consider options from these guys: https://www.bavsound.com/
