I got hold of a cheap MZR 1.8 out of a 2007 Mazda6 a while ago.
I will use it as spare engine so for next season if the 2.5 problems persists/escalates...
I'll keep it all stock and probably use it for the next periodic vehicle inspection to avoid any drama.

The engine does not have DBW.  It also have a 36-1 tooth pattern crank and 1 on the cam (no VVT)
So I'll need to swap that out with the 1.8 NC cams and pulley that I have stashed away someplace.

The FWD non catted exhaust manifold looks pretty decent. It has a divider inside the collector so actually a 4-2-1 layout. My guess is that this is a EU only model that does not need to have as strict emission as the NC which is probably all markets. (precat, dbw, other ECU)