I just finished building my LCR HT-8 speakers and put them in place over the weekend. I love them so far. The hardest time I had was getting an acceptable paint finish even though these will hopefully live behind an AT screen in the future. I've read about Marty and various other huge ported subs, but I'm leaning toward the 4 cu ft sealed enclosure with a UM-18 instead. I notice DIYSG has a UM-18 flatpack and it appears Parts Express also has the same flatpack bundled with the UM-18 woofer. I'm coming from a small 8-inch Definitive Tech powered sub, so just about anything will be a huge improvement. I have one channel left on my iNUKE NU3000DSP and hoped to drive the sub with it. Are there any considerations I might be missing as I pursue building one or two 18-inch subs? Thanks!