I use FSX-SE and bought the C90GTX a few weeks ago and I have experienced the same issue with this aircraft turning left during takeoff run. In FSX the P-factor and all other controls are set to easy, but the aircraft is obviously not responding to these settings. In my experience from real life flying, the left turn during takeoff is way too much. I am looking forward if someone has a solution to this issue.
Regards
Erik Bentsen