Calling all Sonic Frontiers "Power" amp users...

I have the Sonic Frontiers Power 1 amp. I want to get some feedback from other users about....

1) Has anyone had their unit upgraded by Chris Johnson (former head of SF) at Parts Connexion? Was it a good, easily noticable, upgrade?

2) I still run my Power 1 with Svetlana 6550C tubes. What do you run? How do you like it?

3) My input tubes are still the Sovtek 6922s that came with the Power 1. Has anyone upgraded the input tubes?

Thanks in advance.

I have not changed the tube compliment that is suggested for the amp...I also have the Line 1 used in conjunction with the Power 1. I would like to here anyone's experiences with other tubes....especially the Parts Connexion suggestion of KT-88s. I am very happy with the current performance...detail and only question is if midrange richness can be enhanced.
If you search the archives there are a couple of users that have had the parts connexion mod and they swear by it. I wouldnt doubt it, SF was an ingenious company. I have a power 2 and i am running valve art KT88, sylvania gold pin 5687s and seimens gold pin 6922s. The change in sound is very noticable. The mids are velvetly smooth like a good merlot. and the highs are crystalline without being harsh. Also he KT88 add a lil bit of power (i think about 10-15%), i not sure if that is good or bad for you. All i know is that i love my amp. In fact, i had a power 2 and sold it to buy a BAT VK75 Special Edition, and i prefered that Sonic Frontiers unit, so i sold the BAT and bought another Power 2, i used the left over $ to upgrade to a new pre and buy a nice stand, good tubes, and some cables. Im as close to nirvana as i ever have been
I got a SFS-50 with a Line-1. I replace the 3MP Sovtek 6922 of my Line-1 and the 4 JJ/Tesla E88CC of my SFS-50 for 5MP of 6H23N-EB from Reflektor(bought at Parts Connexion). Wow, what a difference. The midrange was really natural now. It's more analogue than digital. And the low frequency is more precise with more definition. It's like if there are no more glare in front of me (the black is blackier like they said). I got 4 Svetlana 6550c in my SFS-50 and it's great. I try 4 Svetlana KT-88 for a week-end(pass to me by a friend) and it was better in the high and a little bite more in the base and mid. So much that my next power tubes will be KT-88.
Instead of upgrading your Power-1 why not sold it and buy a Power-2. I think it will cost you the same amount and you will have a 110w/ch. Or change your CD player for a better one and buy new tubes.
Hello and thanks for the replies so far. I did spot the old postings which refer to Parts Connexion upgrades, but the posts were fairly old and I thought I might put it out there again.
I'm definitely leaning toward a tube upgrade. PCX has recommended JJ Tesla KT-88's and NOS Siemens gold pin 6922s.
Upgrading to a Power 2 is an interesting idea, but if the upgrade provides nothing besides extra power, it wouldn't be for me, since the Power 1 has ample power for my system.

More responses are still encouraged.