I'm back from the hospital, back from the jungle... god, i love snow, compared to that horrible, damn swamp for a jungle they have in Colombia...
Anyway, the question here is about the Mp5 SD... I used one in Croatia, during my time there, and i can honestly say that i love the gun. The truth is, that when you carry it around in the field for a while, the suppressor _will_ take some damage, and thereby lose a lot of its capacity. It will still, however, allow you to use it very efficienlty in night-time operations.
With proper night-sights, say a good optical tritium-sight, you'll scare the **** out of your opposing forces.
Now, it's time for some proper R&R, there's a pub around the corner..