I went with the (cheaper) OEM 29 liter topcase. The 30 liter is ridiculously expensive. The 29 liter one is surprisingly inexpensive & works quite well. Also fits a full face helmet. Also, I got the dealer to include the topcase with free installation as part of the bike purchase agreement. However, buying one outright is not that expensive (for example, $201.99 at sierrabmwonline.com). Also, it can be easily unlocked & removed from the rack if desired.
Last edited by Tripod; 10-03-2018 at 12:54 PM.