i wouldn't start cutting all the wires. it's bad practice to burn your bridges.
it doesn't hurt to just unplug the wiring. shoot it would only take me about ten minutes to do that.
if you want to go with painless then go ahead but why not have a god stock harness in your hand incase if they send the wrong one, or your buddy needs it, or the painless one gets damaged in shipping. what ever. it just seems to easy of a thing to do to me to not do it.
