Well below about 35hz the pb/PC2k is a better option than the sb3k. But anywhere above that the sb3k wins. IMO you should be looking to have at least two subs, and ideally they’d match. Two pb/pc2000 pros would be a very big upgrade with more extension, more output, much less distortion and the ability to help smooth out the response. I personally think that the rsl 12s is a better subwoofer than the 2k series, but you’re already in the svs ecosystem so…..maybe a pair of pb3000’s?