Tube-rolling...PrimaLuna ProLogue Three

Any interesting results? I've not listened to anything but the stocks that come with it. They sound so good I haven't given it much thought but if anyone's heard something noticeably better I'd be interested in doing the ol' switcheroo.
If you could fantasize an improvement what would you want to change by getting a different tube?

If you don't have an answer, save yourself the time and money you will chase after new tube recommendations. All tubes will effect to some degree or another the tone, for goood or bad, often depending on the sources and amps you are using. FWIW.
Newbee is spot on with his advice. The stock tubes that come with the Prima Lunas are pretty decent and will serve you well. If you can identify in what direction you want the improvement, then the next step is to call Kevin Deal at Upscale and ask for his advice.

For my Prima Luna 2, I wanted to smooth the bass out a bit and went with Svetlana SED Winged KT88's. Good move. I read in a post Newbee (? or maybe Tobias) had ultimately gone with 6550's. I tried those, just to try them, and felt that they bridged the El34 sound and KT 88 sound nicely.

As for my Prima Luna 5, I have kept the stock tubes in place without looking for anything else.

Regards, Rich
I have just substituted the Shanguang triple-mica 12ax7s for the stock tubes,it's a nice improvement and not expensive.I was turned on to them by a good friend,heavily into tube rolling.These list for $10-12/matched pair and as I was told are reproductions of the Telefunkens.My friend has had them in his amps for three years,so the comments about a short life-span maybe untrue-time will tell.
Next will be the 12au7s-have some neat French cryo'd ones to try.Hope they work as well,seeing that they ran $45/ea.