Any speaker amp should work, given they can be connected, but some may sound different.
If you get a STAX adapter instead of an amp, make sure it is PRO bias and not Normal bias if you are going to use non-vintage headphones with it.
I owned the following STAX equipment:
SR-207 electrostatic headphones
SR-30 electret headphones
SRM-212 electrostatic amp
SRD-4 electret converter
I got the electret system first and used a Lepai LP-2020A+ speaker amp with it. The SR-207 sounds significantly better than the SR-30. I'm not sure if all electrets are like this, but the SR-30 distorted very badly whenever there was high volume and/or heavy bass in the music, so I had to lower the bass and/or volume to get rid of the distortion. The SR-30 also works fine from electrostatic amps. I did not hear a difference between driving it from the electret adapter plus speaker amp and the electrostatic amp.
I would recommend going for a used electrostatic system. You don't need to pay a lot for it. I only paid $180 for the SR-207 and $150 for the SRM-212. (Though I got lucky.) If you can't find one that you can readily afford, electrets are a good introduction to the magical transparency of electrostats, but trust me, you're going to want to upgrade to the real thing sooner or later.
Also, about the names...that system you mentioned is actually called SRS-3100, which consists of the SR-L300 headphones and SRM-252S amp.