 Original impression of X3 3.0si on test drive was quite positive. I purchased a certified X3 3.0si with 12K miles. Car handles well and has powerful engine. Transmission is erratic at best. Sometimes does not engage at all, others shifts very hard and can cause nausea in passengers. BMW service can't find issue which suggests that they have not figured out optimal transmission match to the 3.0si engine in the X3.