Yes, but not a lot. I have a jato 3.3 resonator (single chamber I think) on my jato with a 2.5. It is a bit louder, but not enough to be of much concern.
If you are concerned, get a silicone exhaust deflector. They take a lot of the sharpness out of the exhaust note, but don't really impede performance.
I can say that you will get much better performance out of your engine with the new pipe.
Yea I love my reaonator pipe, its not too loud but its got a nasty tone to it! Also I have a question... are the holes on the resonator pipes that come with the 4908 smaller than the ones you buy? I watched a youtube video about some dude comparing 4908 to 4909 and he said the hole was smaller on the 4908 than the one he bought for his 4909. Does this make sense?