If you've got 160k on the clock there is no way the car is in top form at the moment. Sorry.
At the very least the injectors are probably over the hill, the fuel system may have problems, and the fact that it stalls is not a good sign.
Stalling can be a number of things, the usual suspects around here will tell you the ISV stuff.
However, you coil could be dying, the lift pump could be dying, the injectors went to heaven a few years ago, fuel filter is clogged up. The list is endless.
If the car was in top form, then it would easily level peg with the GT till about 70-80, and then it would be murdered. It'd be GT in the rear view mirror time.