I just pulled the aftermarket starter out of my 94 XP that stopped working while I was cranking the motor over. After taking it apart and cleaning the contact surfaces it would only spin fast enough to throw the bendix out if I had the charger set for a 50 amp output, even then it was barely enough to move the bendix. Something in the windings failed, the battery, cables, solenoid all are good. A good starter, on the bench, should slam that bendix out with a snap. This is the 3rd aftermarket starter I have gone through, all failing in the windings in a similar way.
Ebay for a used OEM starter, sledgehammer for the old aftermarket. Problem solved.
I also have a 97 GTX and am suprised at how many times the low battery warning pops up when my DOO is running perfect. Just make sure it is charged and in good shape.
Like Mikidymac said, pull the starter out and check it over on the bench.