I've got that set-up & love it. I can be quiet when I need to, but it definately gets attention when I get on it. It's a good choice for a street car. I've driven right next to police, and while cruising, I won't get a second look on account of the noise level, not unless I open it up.
No drone, I even drive regularly without my rear seats, and it's very quiet while cruising. I put on the catback after the prochamber. I don't feel qualified to point out differences between the prochamber & magnaflow X, because I've never owned a magnaflow X.
I will say that I'm very satisfied with my prochamber. It perhaps won't last as long as a stainless steel magnaflow X, but I'm in California. The car never sees road salt in the winter, and it won't be long before the car is no longer my daily driver, so it's not as much of an issue for me.