The only OBX topmount I had experience with (it may have been generic china, but was thick walled which I associate with OBX) required a T04 on center turbine housing. It was on an EM1 chassis, and the guy only had a tangental housing + decided to cut into the headlight frame and run no hood to make it work. Not what I would have done.
Be ready to test fit and take that right off, ED are a much tighter chassis with less clearance.
FYI, made 422 whp off a B16 with 60-1 on that manifold, sprayed a 100 shot and made 574 with slicks breaking free at 7500 rpms. Local heart breaker Mustang dyno. There's nothing wrong with those as far as power production, and the one I'm thinking of didn't have any cracking problems.