If you're looking for an rw12D, Consider the Polk PSW505. They measure very very similar, and have been offered on newegg for CHEAP, like $160 or so. For the price of 2 rw12ds you could have a polk 505 in all 4 corners.
Personally, if I was budget limited and wanted a decent subwoofer, I would look for multiple cheaper subs that reach into the low 20hz area than a single more capable sub. The benefits of multiple subs are more important than the benefits of a few extra Hz of frequency extension and SPL to me.
All said and done, 99% of the people in this forum would be very happy with dual rw12d's, or Sub12's, or Polk 505's once set up properly.
Of course, after going DIY, I will never look at another pre-assembled sub again. "SPL @ 30hz ? Come on, what will it do at 10hz ?"
The problem is that cheaper subs cant do low 20's at high SPL without distortion. While adding 4 cheaper subs may give smoother bass over 30Hz or so, the relative SPL of the low 20's is still going to much lower compared to the lower 30's and the relative distortion is going to be higher compared to the low 30's.
So multiple cheaper subs may not always be the best alternative to get the low end extension for movies?
I live in a 1500 sq. feet ranch and my living room is like 23'x16'. I use the tiny Sunfire Tru Subwoofer Junior and never felt that need for more bass. Since I am the only listener I also didnt bother about evenness across the room. I did try the SVS SB12 NSB a couple of years ago and didnt notice any improvement in the bass. I also tried the RF82's, RC-62. I decided that the KG series (3.2/4.2/4.5/5.2) along with the KLF-C7 is a better value. So I got rid of all those more expensive stuff. I didnt lose a lot of money selling the RF series as I bought them already for a great deal. When it comes to cars and speakers, used is the way to go