I believe the n1 bypass is just to ground the parking brake wire..., the n2 got a little smarter and made people solder a connection to bypass into European mode, then the n3 had a switch because too many people were destroying their n2's trying to bypass, the n4 you have to add a wire to the harness in the back and ground that as well as the parking brake. In all models the parking brake needs to be grounded. the n5 however, i have no idea about, but that's because it's not out yet, hahaha... I've gotten all this info from these forums over the past years so if anything is wrong please post
