The cars are competitive in ITA/ITS now. I don't know if these competitive cars have depowered PS racks or not, but I don't think anything is going to give you grief over it. It'd be nice to see the rules changes to allow folks to remove PS though.

However with a bit of work you can de-power the rack: pulley on the PS pump that is an idler around a bearing pressed on the PS shaft, remove the innards of the rack (i.e., my rack is busted), remove the vanes in the PS pump (i.e., my pump is busted). That said, I love the PS on the Mustang and feel it is a contributing factor to it being a very tossable and easy car to drive.