I am looking to do a pair of sealed either 15" or 18" subs for my HT to replace my ED A2-300's. I am trying to decide whether to do a pair of 15" Titanics or the RS series 18" from parts express? Which will yield more output and better SQ? I know the excusion on the Titanics is better than the RS but the 18" is larger in size....What do you guys think? I am likely going with another of the flat packs from DIYSoundgroup after the ease of construction on the sealed 10" subs project that I am currently in process on. Do you have another other suggestions for drivers in a sealed box. My Max Budget for each driver is $250 a driver. Thanks!!