Need advise on amp choice

I have done intensive reading trying to solve my dilemma but still no success booked...
I have got a pair of SF Strads, an ARC LS26 and I wonder what would you do if faced with the following choices:
- used ARC Ref110, 3 years old with 1643 tube hours for the half of the original price
- used ARC DS450, 2 years old for the half of the original price
- new ARC VS115 for the price of the above mentioned Ref110
I am a little worried about the noise made by the 2 cooling fans in the Ref110 since I love the silence between the tracks; it doesn't have the latest KT120 tubes and, according to ARC site, I will have to invest soon in new tubes anyway...
I have had a new dsi200 for 5 months now but it wasn't by far a match for the speakers, luckily I was able to sell it.
My dealer insists on buying the VS115 but it's in the run from 2008 and, following the company policy, it should be discontinued sometime next year - not a much of a reason but still...