Hondata

Ya the more reading I do, it's better off to save up and grab a s300. I need a obd2a to obd1 harness and a p28 right? Or can I use the factory gsr ecu?

I found a good deal on a s200. I'm wondering if it does not have the boost add-on can I still get it? The setup is a stock gsr motor intercooled with 550's and a 16g style turbo. Also is there Anything I should look for when buying a used hondata??