Surprising you havent heard of them as they have been the go-to for clutches for the older mazdas going back over a decade. Their website is a bit behind, but if you call them, they have a listing for the 2.5.
I myself didnt go with there off the shelf 2.5 clutch. I actually used the stage 2 Drag series clutch they sell for the older Mazda FS 2.0 motor and trans. Its also a G series like ours. But the FS pressure plate has an even higher clamp rating, as well as being an extra 1/2 wider disc area. That, along with the Throw out bearing being all metal, instead of the half metal/half plastic throw out bearing used in the MZR clutch kits which i never liked.
Im in no way saying others should go out, and use a Mazda FS clutch or anything. Just with my research, for my specific application, i decided that was the route i wanted to go.