Like someone said above, I have heard that if you overtorque your lugnuts, it can help accelerate the warping of your rotors. There is no way to tell, using a wrench, how many ft/lbs your lugs are tightened to. I think you could "borrow" one(torque wrench) from AutoZone, they have a tool lending program there, I think you put down a small deposit, get the tool, and when you return it, you get your deposit back.