Sub under deck

[Unregistered]

I'm building my deck in the early spring and will want to do a nice setup for outdoor parties. We will have many of these functions as our neighborhood consists of many young couples ( 8 couples that we hang with are 24-30, we are 25). The neighbors will be over many times to party so I don't have to worry too much about volume. I'm thinking of going with the Niles OS20 or 25 (25's go down to 58Hz instead of the 68 from the 20's) if the price is right, but I'm wondering if I should put a couple subs under the deck. I would just buy some cheap 8-10" subs from ebay. I would put a screen over the port holes to deter little critter from making homes in the box and wrap them in thick plastic to keep water and such out. I could bring them in the house for the winter months as the deck will be rasied 5'. I was thinking of splittling the sub signal from the receiver to my SVS in the living room to the 2 I would put under the corners of the deck closest to the house. Anyone ever done this?? Is it overkill!!
BTW they love my system and I've now got 5 jobs lined up!