I don't have a 3-series so perhaps that makes me a troll in this thread.
Nothing special in my collection. I've come close to pulling the trigger on a Speedmaster and IWC Portofino a couple of times but always ended up buying camera lens instead.
In the meantime, I cycle between one of two Seiko Sportura chornos, a Hamilton Auto Chrono, and LumTec Combat B8 chrono. I think I only have a pic of the LumTec at the moment (composition is off but hey...this isn't the photography subform
). The shell is a souvenir from a work trip.