I am contemplating changing to a tube amp to run my Sequel IIs I am currently running a ARC D400 at 200 watts per. My question is what type of changes in sound should I expect from the change and how much power would be the minimum I need? (I like my listening on the loud side) My short list so far includes ARC VT100 MKII & ARC VT200. Oh by the way I run two Velodyne FX12 subs in my system.