See the following thread:
I have purchased the Concerto Plus SE with built in quality step up transformers for MC.
You will never find this quality in build or sound for less than $3,000 or more. It is awesome.
I also purchased the Amplifier Sonata SE with KT88PP.
Not Chinese tubes.
It blew away my 211's
Just have them upgrade the amplifier you want to Tango power and output transformers. Very low insertion loss.
Better than any amplifier i know of. Most transformers on other amps have a much higher insertion loss.
They are very good to work with.
Tell them your current system speakers etc. and they will help you get the best product for the money.