Hopefully Cody and other stroker owners in Texas will chime in. I have been waiting to post my initial impressions until I got more familiar with the new engine. I just got back from a little drive and achieved a 4.0 second 0-60 on my Performance Box with little effort, as I did not use LC or a drop clutch launch and shifted a bit too early. Ambient temp was 65 degrees. Atlanta altitude is 1000 feet.
The first thing I noticed with the engine was significant wheelspin throughout the rev range. I began to be concerned that traction would become more of an issue than I had anticipated. My PS2's were still good for another several thousand miles, but I changed them out anyway, and this made a considerable difference. Based on driving perceptions and Performance Box times at 10 MPH increments, while the power is increased throughout the rev range it is most prominent in the lower RPM range, which is exactly what I wanted given the the lower torque off the line in the stock M5. Additionally, I no longer get the kick in the back shift from first to second, but do get it from second to third. Not sure why, but I am guessing that it is due to the flatter torque curve of the stroker engine. Dinan seems to think it is also due to the lower reciprocating mass.
All in all so far I am pleased with the engine. Certainly not as powerful as forced induction and nitrous options, but it is giving me what I wanted--great throttle response of a naturally aspirated engine with significantly increased torque over stock, particularly where it previously was lacking in the lower RPM's.
