I recommend Redline as a very professional shop with more than one well informed Guzzi mech. I assume their per hour rate may be on the high side (I don't know) but I am sure it is made up in they're efficiencey. The three other dealers I have stopped at had not even seen a new Stelvio yet but these guys have at least sold one. They're main focus looks like Ducati, also carrying Motos, Aprillas, and even Harleys. My bill reflected a lot more than just the tune rounding out at about a grand. I had them chasing down a constant wobble since the bike was new and it turned out to be a bad front tire from the get go. The new PR3 Trails are straight and true. I will say the ECU charge was a lot less than we have heard but that may be because of all the other work that was done.
I once was lost but now I'm...no wait, I'm still lost