@yyzsantabarbara, The Sierra-2EX is a poor design. The problem is that the tweeter is going to convert from point source radiation to line source in the upper midrange depending on the length of the ribbon. Line source speakers are more efficient radiators so, as you move away from the speaker the sound is going to get brighter and brighter. A speaker has to be either line source or point source. It can not be both. The problem is that as frequency drops the speaker has to get taller and taller to maintain it's line source characteristics until it is as tall as the room. Few wives are going to like that. I got lucky.
@mduffy18d , If you have any mechanical talent go to Parts Express and check out the subwoofer kits. You can build great subs at 1/3rd the price and have them finished any way you want. The best would be a white polyester lacquer. It will take a pro to do that.