For movies, I'd go for option no.2 as Corr says. That way you will be using both voice coils of your Diamond woofer.
For music though I'd go with the high level inputs by piggybacking a pair of speaker cables from your amp's L and R terminal to these while setting your speaker size to Large or with bass management off. This will make your VR-S1s work pretty much the same way the active woofers on your DB-99s do.

Don't do both at the same time though.