The 12200411 PCM is preferred chioce. Found in 1999 to 200x cars, trucks and vans so there's plenty of harness to be found.

EFI Live, HP tuners software will set you up to log and flash, there is license fee per PCM. You can also still but a simplar TunerCat OBDII (no license and no data logging) if you buy a RoadRunner from Moates to tune Real Time. ScanXL Pro with enhanced GM PIDS will do all you need for data logging. None of the options are cheap.