not really the nxt is a awesome gun as standard, you need air, if you run it on co2 il personnely snap your fingers off, yes your on/off will fit, dont mess with the settings of the nxt when it comes, if its not broke dont fix it, the only thing i would recommend getting is some 19/50 o-rings for the bolt as they do go every so often but that is it, no real problems the trigger is sweet as it is, get a freak back instead of the all american other than that its fine.