Not at all about emissions. The 2.0 and 2.4 were and are under powered for most of the applications they were used in. Also these engines were never meant to be rebuilt so unless you were changing basic components you were better off buying a brand new one. Generally the rebuild cost was more than new.
You also might want to check CARB as they have different regulations for on road and off road.
Also it was not Daewoo in bed with GM but PSI and Daewoo working together. GM just manufactured to the OEM's spec but then sent to people like PSI to put the final fuel and other OEM spec parts on them. There a few companies out there that do this with PSI being the biggest.