On the Tire Rack LM-R's the OE 19" sizes: 245/35R19 and 265/35R19 will work fine. You can get new tires if you want, but if you have a set of stock 19's, they will be fine.
I have accepted a new position at Tire Rack and am no longer in the sales department. firstname.lastname@example.org
is available to assist with M3 questions.