Time for some Maxima mirrors!
I think RPsport is dead now, and I think the S14's subframe is supported better I think.

Looks like it's bolted straight to the body instead of a thin piece of metal like the S13.
I'd check the diff bushings too, replace em with solid bushings.
S13's diff is mounted solid and there's no problems.
I finally sent my manifold to Motoman.
Man, cutting the flange off the KA manifold was a pain in the butt.
But, I learned that if you cut half way through it and smack it a few times with the hammer it falls off.