Supressors do not lower your power, they may seem to but they just reduce range, which is quite annoying in itself.
Suppressor = Lower range = Lower power.
For example a suppressed Famas starts losing range and power at ~ 12.5M
But yes, I run a suppressor on my Ghost class.
Yes, at range it loses power, thats the whole point of range, the further away you go, the less power you have etc. However at, for example, 10 yards, (close range) having a silencer or not will not make a difference in the power.