Dinan has their tune available for the 340i and 440i with the M Performance Pack which should be pretty close to what the X3 M40i comes with stock.
https://www.dinancars.com/product/d4...ries&mid=1237/
They're pretty conservative and their initial dynos had the stock cars at 378/395 with their tune taking it up to 426/463.
http://files.dinancars.com/webresour...1655-ST1_5.jpg