Simple,
I just got my REL Strata III and am still in the process of blending it in. So far my impression is overall favorible. The Strata definitely adds MUCH bass to Special 25 indeed. The bass sounds like natural extension from Special 25, unlike the PSB subwoofer I have. This is THE most important quality I am looking for for a sub.
For movies with DD/DTS, the Strats sound a tad bit less authoritive in handling explosions. While this may NOT be true since I am still moving the Strata around and tweaking the knobs ...
Abe