The Wire-Plus WP374 kit comes with two separate modules. One is the Lighting/Ignition/Starter control module and the other is the Handlebar Control module.
If you decided to change up bars down the road, you could change just the handlebar control module by buying the HD module from Wire-Plus. BUT, you will probably have to pretty much rewire the entire top end of the bike to do those controls without a big BDM to HD control solder/adapt issue.
So, I would say, make up your mind before you buy the Module, because if you have full intentions of changing the Handlebar controls, you would be further ahead to buy the Wire-Plus comnplete backbone harness and chassis control module and completely rewire the bike.