The stock ones seem to be 102 amps.
The REMY Part # 12114 is 125 AMP & only $25 more at $151 sounds pretty good.
You can get from Quality Power a 140Amp (105 amp at idle) for $160.
GM CS130D high output replacement alternator

Delco or Delphi.

The P0620 code on my Buick Rendezvous was caused by a bad regulator circuit in the alternator. A 5-Volt signal comes from the PCM on a red wire that goes to the L terminal of the alternator plug. The PCM monitors the voltage because a bad regulator can load down this voltage. When this happens, the battery light comes on. When the alternator wire was unplugged from the alternator, the voltage was spot-on 5 volts. When I plugged in into the alternator with the engine running, the voltage went down to 1.2 volts. The battery passed a load test and the alternator passed the test at the auto parts store, but the red battery light was still on and the P0620 codes was set. The first alternator I got from the auto parts store was defective. It pulled the 5 volt signal down to 1.4 volts. I called the 800 number help line that came with the alternator and the technician said the 5 volt signal should not be pulled down like that. When I demanded another alternator and installed it, the new alternator worked OK. The 5 volt signal was reading 4.46 volts with the engine running. The battery voltage under normal conditions comes to 14.4 volts.
A funny thing I noticed was that a Wheel Speed sensor problem went away after getting the good alternator installed. It was usually the right rear wheel speed sensor that was setting a trouble code. I have not seen it since replacing the alternator.