Lincoln/Mercury Repair: 93 grand marquis, grand marquis, timing chain

Question
My new car has 135,000 miles, the transmission is new, I plan to get a tune-up soon but I'm concerned about the engine.  Was hoping to get some suggestions on a few things you would check/replace to make this used car last as long as possible.  Someone told me to replace the timing chain at 160K miles.  I have had a car that the timing chain broke and totaled the engine so I am concerned about this.  I have a friend that could probably replace it for me for cheap.  What do you know about how to replace that?

Answer
Usually the timing chain as far as I know is a chain which it wont need to be replace (I'm sorry I cant remember details for cars that old!). I just bought a use one my self with 118500 on it. The only things I did is to replace the spark plugs/wires, check the coil, engine belt, fuel filter, air/oil filters, all fluids check or replace. The car is like new! If you just got the car do the same.