either one. they both work well.
Since you went with SD2, go ahead and download tunerproRT software and locate the .xdf definition file for SD2. It's much easier and much more convenient using tunerproRT to edit the SD2 BIN files than it is to use the powerlogger. The definition file for SD2 is located on the turbotweak support board and it's also posted around here in a few places too.
I think if you log into the racetronix support board you will find the fuel injector offset data that you need to get your injector offset calibration setup to precisely match your injectors. that's where you want to get started. Having the injector offset right in the beginning is very helpful later on. Most common turbo buick injectors are characterized on that support board.