BAT VK-60..New to tubes...Help???


I am looking at a local sale for a original VK-60 with original tubes in mint condition.I want this for a active system to run MIDS ONLY(maybe mid/hi later-passive).I need to know how much it will cost to retube with a warm sounding tube and a fair price for this older amp(1995 I beleive is when they came out???)..Is there different versions?
I will power a dual ATC 75/150S/side active setup crossed at 400hz/3500hz and will need a warm sound.
Any help guys is appreciated.
thanks
NEW TO TUBES
John
mclsound
Thank you Peter and Rodman for the advice on the 6sn7s. I hope I answered your question John.
There is a vk-55 on the gon right now for $2500 that I would get if I had the cash on hand. I don't due to an ugly recent divorce but you could take advantage of it. I think I paid about $2000 for mine on the gon. You might offer him around that.