Ok, so here's my two cents worth....
My understanding is that the SS mod by itself is not a gain mod. (MJMP correct me if I'm wrong). I asked specifically for one without the gain mod included because I want to keep my clean tones clean.
A bit of history first...
My mp1 started blowing tubes and so i took the plunge that it was something on the tube board and bought a replacement from MJMP's mod shop. I did include the noise mod, so he sent me a beautiful new tube board and a whole slew of bits and pieces to replace on the main board.
When I put it all back together it was a different beast. I was getting waaay more gain and some high pitched whistling on some of the patches. I can only guess that the old tube board was fading gradually over time and that my patches were creeping up to compensate. I most likely didn't notice this because I went through a long period playing mostly my Marshall. I finally got around to getting some rack effects gear (TC g-major 2) and then re-did all my patches anyway. Perhaps because of this I didn't notice the gradual loss of gain. So, once it was all fixed, it blew me away. I actually had a patch with OD1 and OD2 both on 10 and I wasn't getting any noise at all!!
Needless to say, the 10, 10 patch is now extremely noisy and is the one that has the high pitched whistling. In fact, that patch no longer exists. I have pegged them all back a bit. And this is without including the gain mod. I have more noise now after having done the noise mod than I ever did before, but that would be because of the lost/found gain.
So, in answer to your question, I can't really provide you with a before and after snapshot of the SS mod. I can tell you that it sounds great after, but I am now thinking that I am going to have to pick up a noise gate.
I've just re-read all of this and realised that I have taken up lots of space not saying much at all. Sorry I can't really help you.
It has, however, helped me. This is like therapy. I feel great. I think I just need to get it all out. Thanks!!