you will definitely see an increase in RTability with the x-valve... especially if you can get your input pressure up into the 900-1100 range. I would recommend looking for an xvalve with an RT on/off if you enjoy the RT action... also if you are new to tuning a lvl10 it is one less thing to worry about (as opposed to an xvalve with a ULT trigger)
As for the hopper, a halo would certainly keep up but keep in mid you will have a lvl10 now... so chopping is going to be a thing of the past. If you do decide you still want a force feed loader I personally am a huge fan of the rotor. Yes they are expensive, but they downright rock and are tough as nails. Also you can break them down for maintenance (which is almost non-existant) without any tools. Just a super solid product all around. ...Ohh yea... and one of the fastest loaders on the market!