The MZR 2.5L has a different head with larger intake ports than the 2.0 MX-5 head. The ports do not match perfectly and the stock 2.0 gasket will not fit.

The gasket is fixed by using Loctite 510 but be sure not to use too much as you don't want that going into your engine.  The POB and silk thread method as is common on planes will also work.
It can also be machined for o-rings but is supposedly a lot of work.

I'm sure there are several ways to match the ports.
I did it by enlarging the boltholes in the manifold downwards such that the manifold can be raised 3-4 mm to have the upper part of the port match the head.  The lower part of the manifold port needs to be  ported the same amount.  I cut out a template from some gasket material and ported it using a dremel. The EGR tube must also be modified as shown on the pic.  It is a lot of work getting the heavy manifold aligned while not furking up the Loctite 510 as you need to manually lift the whole SC manifold assembly by hand while tightening the bolts.  I have done 2 trackdays after this mod and there are no signs of the manifold moving.



Why do this ?  Good question.  I tested before and after with virtual dyno and did not see any noticeable difference in the numbers.  A little disappointing but nice to cross this possible restriction off the list in the hunt for more hp.