I've once had an odd incident happen to me.
I had a 335 an a friend of mine had a 535 e60. I accidentally took his key and while my car was open I started it up. I was amazed that the other cars key did this. Just to make sure we tried my key in his car and it worked as well. The key wouldn't unlock the car however and it also didnt work on a 328 we tried. Just between the 2 cars. So weird.
-2015 AW M4
-(2012 | Laguna Seca Blue | Rust Brown | Individual | 6MT) SOLD