Just curious,
Is the engine in a miata the same as the dohc geo storms?

no. Geo is made by General Motors and mazda is Japanese. The engine code for mx5 is BPT (mazdaspeed), or BP I4 (LS, SE)

Hope this helps

I recently got a slightly damaged Miata, but my specialty has been the Geo Metro, which is actually a Suzuki Swift and imported under the Geo name. The last post did not seem quite accurate so I did a brief researh. A quick correction (from Wikopedia)... Geo models were manufactured by GM in joint-ventures with Japanese import manufacturers. The Prizm was produced at the GM/Toyota joint-venture NUMMI assembly plant in Fremont, California, and the Metro and Tracker were produced at the GM/Suzuki joint-venture CAMI assembly plant in Ingersoll, Ontario. The exceptions, the Spectrum and Storm, were entirely manufactured by Isuzu in Japan. Maybe that is useful infirmation.