I have a backyard sound system with a Rockustics APSS-1 which consists of one 100w 8" sub and two 5.25" satellite speakers. Sounds decent but not really happy with the output of the sub in this relatively large yard. Rockustics also makes a 200w dual 8" sub rock (punksub) speaker and I'm thinking of simply switching out the 100w for the 200w to get more low end. Also, the specs on the 100w is 8 Ohm and the 200w is 4Ohm. Is this an issue?

If anyone has any experience with these speakers or can make any suggestions I'd appreciate it. Rockustics are big $ and I want to make sure
I'm going to achieve my goal before spending the money.

Thanks for any info.