I have an ARC LS 25 MK 1.........

Good comments above. I kept my LS-25 at MK I for the NOS Tubes for the reasons stated. I have done A/B audition between the MKI & MKII and I also feel the MKI is more musical. I also feel there is a synergy if you place all of the ARC latest products together -- I heard a CD3, LS-25MKII and VTM-200s on Vandersteen 5s - Incredible!

I think the main reason for the change to MKII was to get away from the quality issues of current production 6922s. As with any update to a product, ARC made the sound better in the MKII vs. stock MKI. I would personally change to the Ref2MKI and sell the LS-25 if you were to throw more $$ at your system... my $.02..

Thanks guys for all the input...to answer some questions...my power amp (for the mid/tweeter) panels is n ARC VT 100 mkll.

I also went the way of nos(tungsram)in my ls25mk1, not a lot of money for a big improvement in performance, less noise, better base&mid range a nice improvement over the stock sovtek.

Do you a suggest that I change my 6922's in my ARC PH3SE phono per-amp as well to NOS??? If so, any recomendations?

J_K, I heard that same setup a couple months ago at a local shop. Your right, made me want to go into debt.