Keep in mind that a bare steel pipe takes alot of elbow greese to keep looking that nice over the long haul. After having one on my daughters RM 125, I would never have one again. At least not on a bike I use all the time.
I bought every pipe that was available a many years back and rode them back to back - same trail, same day... This italian pipe you desire wasn't available and the gasgas available in europe/canada came with a messico back then.
The doma pipe was the best by far for smooth tractable power with a very, very nice top end - the newer gasgas oem pipes look like a copy of the doma to me; I think the oem pipe will be hard to beat and if it were me - the first pipe I would look at to replace it would be a doma.