[slammedLT1]

MDF for stereo systems is like beer for superbowls. You can't have a system with out it. The truth about MDF is that as dense and hard as it is , it is actually very pourous. A test was once done using an industrial vacuum and 6 circular pices of MDF stacked up together and the vacuum picked all of them up as one. Go figure.
The best thing to do is get your box together and caulk all the crack, around cut outs and everywhere else you may think it might leak and coat the inside of the box with fiberglass resin. If you want to spend the extra time use matt fibreglass on all of the enclosed joints in the box. When it comes to stereos I find that alot of cases it comes down to the solidity of the enclosure and not always the price or type of sub.

Just some Xtra advice... hope I helped