At some point back there Mark had me take a look at his RS Rocket line. Most of them were a bit of a miss. The responses were really rough and the break up areas of the metal cone woofers were not addressed.
Here is a measured response of an RS 1000.

And here is the spectral decay.

So I designed a new crossover for them that corrected those problems.

And the spectral decay of the new crossover.

I did the same thing with the RSC 200 or Bigfoot center channel.
Later RS 1000's, RS 850's and RSC 200's were produced with my upgraded crossover design. So some later versions did get an upgraded crossover, but most earlier versions did not.
So the earlier versions can be significantly upgraded.