I haven't, but I have thought about it a few times.
There are so many turns to the system that it looks like it could benefit from a little work. Same with the exhaust, there are several bends to it as well when you look at it.
I don't know if the 2.5 moves enough air to make it a worthwhile investment though. It might make zero difference, except at wide open, which I don't actually run at that often if ever.