I've had a couple of rifles over the years with those after market rams and never liked them.
Harsher than the adjustable power rams fitted to Theoben's own rammers and the hw90.
If the rifle's a keeper I'd be tempted to return to standard as a springer.

Then again on the subject of scopes, I've never had a gas ram rifle (or any springer come to that) destroy a scope. I've never used a dampa mount either. Just good quality mounts.