Usual tyre size for 19” wheels on a 350z front is 245/35/19 and not 245/40/19 which would have been the tyre size for when they was on the 370z. Rears are the same for both 350z and 370z on 19” as you said 275/35/19. So I’d go with 245/35/19 for the front, which means you can have MPS4S all round as it’s not best to mix tyres even the two Michelin’s. Especially if your buying all four at the same time, as that seems daft to me and would drive me potty. Haha