There's more in what makes a good subwoofer bedsides watts. That PL200 isn't really a significant change. It's almost a lateral move.
If you really want an improvement, save yer ## for something from Hsu, SVS, or some other dedicated subwoofer manufacturer. Figure on at least $500.
FYI, I have an F12 and, for the $$, it's a really good performer.
To adjust a subwoofer, set the crossover so the sub takes over where your mains stop reproducing, to minimize the overlap between the two. Kerfutz with that and it's level control until you find a good balance.