I would go with a 245.35.19 front and a 265.35.19 rear.
The 245s are 25.8" tall and the rears are 26.3" tall, as long as you are within .3" from OEM you will be fine.
2013 M3 Coupe-MR/BLK ZCP, ACM test pipes, BPM Stg2 dev. tune and Megan catback, more to come
Previous rides: 2011 M3 Coupe-MR/Blk
2007 Porsche 997C2S Speed Yellow/Blk sport seats
2004 BMW M3 Imola/Blk