Get the BD, drive it and have fun and when the BL comes around upgrade and sell the BD. Seems pretty clear to me. Gets you in on the fun but allows you to test out what you want/need/dislike/etc so you can better fine tune the BL
For instance, maybe you're happy with the sound in the BD. No need for the B\O stereo so now you can start testing your needs on the other Lux items. Maybe you dislike the MGV on the BD which causes you go to leather on the BL.