Thats right, for an M Z4 or Z4 M Roadster - you'll want to get 19x9.5 ET20 on the rear and Fronts 19x8.5 ET 38. Tire size you'd want to get is a 245/35/19 and a 275/30/19. Give us a call at 714.459.5597, we have lots of different tire options available. Or send myself or anyone else an
email, and we'll help you out with any questions.