Just to give you guys an update on my progress. I ended up purchasing the Dayton MKII Titanic driver from parts express not the MKIII. I will be putting this in a 16x16x16 inch cabinet. A co-worker is an expert cabinet maker and so he offered to build the cabinet as long as I provide him the cabinet plans. I haven't decided if I will veneer the cabinet or just sand and paint it black. I have spent a total of $147.00 so far. This includes the driver, terminal cup, and hex head screws for the speaker. This will be a passive subwoofer driven by an external amp which I already have. I figure the wood will cost about $30.00 and of course I will pay my coworker some small fee for building the cabinet for me. All in all it appears as though the project is going to come in under $200.00. Not a bad deal I don't think. The reason I decided on a DIY was mainly because of price. All the store subs I looked at was upwards of $400.00 and I did not think the drivers were very good. Well, I will keep you updated as the project progresses.