Well, first off, I mis-titled the thread! Bah. F30, of course, not F10.
Neither, exactly. No factory system ever has an output for an extra sub. However, the 2013 F30 with H/K has a few oddities that will make it harder for most install shops to add a sub than in the previous platforms.
Our kits for the E90/92/82 include the plug-and-play integration harness and components that fit under stock panels, and all wiring harnesses pre-wired. You would be adding another amp - and when this first enclosure goes into the F30 which it's already assigned to, we will send you pics of what we're talking about specifically. Our Add-A-Sub packages let you add a sub and an amp without cutting a single wire in the car and without modifying the car in any way.
musicar northwest portland or musicarnw.com
Web site migration complete, still repairing problems. Sorry!