I have heard this from a couple people over the years. Im talking purely based on the PCM, no smog restrictions, cats, O2's, identical setups etc.
Has anyone seen this personally on the same car before and after the swap or heard this besides me?

 

Its all in the tune you put into each... obdii is more comprehensive.. and on obdii there is also torque management.. but it will NOT make the engine run slower.

 

That is a complete myth.

End of story

 

Cool, thats what I thought, thanks.