viper 5901 into a 2005 nissan 350z

that wire will power the accesories in the car, that's the wire that gets current at the first position on the ignition switch, like deck, mirrors, clock and so forth, the pink/white wire will do second ignition which does the climate controls,

although it really doesn't matter how you connect it,

and yes you're just splicing into the wires

you can connect it to the one wire at the ignition switch, but me i personally run all three via three ten gauge wires to the battery, if you choose to do it at the ignition switch however, set your votage threshold to low, when it's left at default high sometimes when the a/c and all the accesories are in full swing it could cause the vehicle to shut off, this is with voltage however, if using tach it doesn't matter

false

yes the accesory wire only gets current via the turn of the keys, so you will have to connect it in order for your accesories to function during remote start, in some vehicles this wire is crucial to proper functioning of the vehicle, not really this way with nissan as far as i know, but leaving it unconnected should do no harm

do not connect the accesory wire to a constant twelve, it will result in your accesories staying on and battery depletion

ok no probs