Buying an un-modded used McCormack amp and then modding it is not a good idea. Better to wait for a Rev. A or Gold level modded amp and buy that used so you get big discounts on both the amp and the mods. My experience is they don't need much service, but if they ever do you know they're very well supported. The bonus is that you can buy one used and sell it for little/no loss if it's not to your liking. Best of luck.
