Ok, I have good news and bad news then.
Good news. Once you personally do the phone restore, turn off "Find my iPhone" and create a lock for using the phone, no one should be able to do anything directly to the phone to track it without you knowing it.
Bad news. Your phone still has to connect to the wireless towers and if three towers can see you, anyone with a warrant can triangulate your position to within 900 meters or less. And by less I mean, if they look at the ping time for each of the towers and do the full math, they can get your position down to roughly a meter.