Get the "Low Power" complete bolt. It's easier to swap and handy to have a spare. Fiddling with RATech's NPAS is a PITA. Their hex tool doesn't actually fit...and you have to hold the valve in place as you turn it anyways. In addition, by the time you cram their NPAS valve into the nozzle it's basically filled and your velocity drops so much that you don't really need to adjust it. If you do, you'll end up sub 300fps. Also...there's been word/observations that the steel npas valve strikes the cross pin quite hard...resulting in broken crosspins/nozzles.
In truth...the only material difference in the bolts is that the "low power" bolt uses the Japanese cylindrical float valve whereas the KWA version uses more of a rocket fin type valve (which lets a lot more gas through).
Dynamo was making some "Low power" float valves...it's in another thread. Basically you take the stock rocket fin type valve out...drop in his cylindrical valve. Still fiddly to swap back and forth....and thus why I say to just get another bolt altogether.
The MP7's work great outdoors...but if you want to do it "permanently"...just get a japanese/Dynamo valve, swap it and be done with it permanently.