I wonder if that had more to do with the Polks than anything in your early revision. The ZX250.2 in bridged mode indicates 250 watts RMS. The 700.5 shows 210 watts x 1 channel for the sub. To me that's no real difference.

On the other hand, I'm sure the cabins would sound better with the 70 watts x 4 ch. compared to my current 35 watts x 4 ch. with the 200.4

I also have an Infinity Reference 5350a that does about 50w x 4 but only does about 150 watts for the subw. I noticed a big improvement with the sub when I switched it out and the in-boat speakers were about the same. Maybe I should just try to swap the Infinity amp for a better 4 channel one or something.