The dowpipe is different, cause the exaust manifold is different too. If you use an exaust manifold from mx3 with mx6 downpipe, the flanges would be offsets.
The lenght of both downpipe are quite different. The mx3 is shorter than mx6/626. You would have problem fitting cat over mx6's...
The "k" series fits perfectly into the proteg 90-94. It has the same engine bay as the mx3.
For this to be possible, you have to:
-gets engine mounts from any probe/mx6/mx3/626/millenia.
-mx3 or millenia exaust manifolds/mx3 downpipe
-curved style intake manifold from millenia/eunos 800...
Not to mention that the "S" comes only in ATX version.....ain't no fun to drive.
210hp...and it stops there. You can expect no gain from what ever stuffs you'll hook to it. All of the goodies would have to be customized.