I need an obd2 ecu for my upcoming emission test. I can get a good deal on a 1999 p72, but is there a difference in p72 from 1999 to 1997. My car is a 1997 with obd1 conversion right now. I s a 1999 obd2b or something like that? Just wondering before I buy something I can't use. BTW Emissions stuff is nothing but a headache is a modded car.