As you know, there is a common belief that sealed subs tend to be more punchy and musical while ported are more extended but like most things there are exceptions. My educated guess is that you will like the L12 better, given that your room isn't that big right? The LV12R will for sure be capable of louder bass. Two L12 may just be the ticket for you if you are going to use the system a lot for stereo. I have one E
15HP in my second two channel system and I can tell you it blends with the small LS50 smoothly to the point if I close my eyes I can swear there isn't a 15" sub in the room. I do believe the L12 will come close just with much lower output.
Edit: There isn't such thing as E12HP, thanks to Kurt who fixed that for me.