Are there any major differences between the P08 and the P28, instead of the specs, since the motors they run are slightly different? Could a P28 be used to run a D15 vtec motor?

 

Yes it can, you would have to do an OBD1 conversion for either. I have p08 ECU waiting for my conversion, that is if I ever get around to doing it. There are some posts about thoes ECUs, Just type in d15b in the search and you should find a discution on them.