I order the Rockford Fosgate P300-10 Punch Subwoofer on Monday and received it today via Amazon prime. The 12" version was really too big to fit anywhere unless I put it under the helm. Instead I measured the seat opening that was right beside the batteries in the rear starboard side. I thought I could maneuver it in there and it ALMOST fit.

Unfortunately, it would not fit there. However, having the Stern Radius floor plan, the reclining seat back in that same row of seats, lifts up. I noticed a panel on the outer back of that seat just behind the captains chair. I looked in and saw it unscrewed and removed super easily. The 10" sub went right down in the hole and I was able to even stand it up on it's side taking up less room so I now have room for some other things in there. The wiring was SIMPLE and that bass thumps SO GOOD!!! I also just noticed another price drop tonight on Amazon for this. At the time of this post it was $170 on Prime.
https://www.amazon.com/Rockford-Fosgate-P300-12-Subwoofer-Enclosure/dp/B007AQ2W2Q?th=1
I also found a killer deal on 2 pair of Kicker 6.5" speakers ($99/pr also on Amazon prime) that should arrive tomorrow. I am going to replace the stock QM-650 speakers with these new ones. Even if I left the stock speakers adding the 10" sub was perfect for my boat. The punch is just right!
Thanks for all the help on here with the suggestions.