ecu question

iv recently put a d15b2 in my rex and it had a 8 valve in it originally (the engine now being a 16 valve) and also it had pfi which was on the old engine im swithching back to the mpfi that was on the new engine originally can i get by with a pm6 chip or do i need the whole new ecu and/or anything else i may need to make this swap work propely please help

The pm6 is for the mpfi with the si dizzy, and si intake manifold and the 4 injectors. If you have those then the pm6 will work perfectly. The head has nothing to do with what ecu you run.