I am considering the BMW 325 in an i or xi package and am also considering an Infiniti G35. First on the BMW, I live in MN and on a hill, do I really need the xi or can I get by with a good set of winter tires? I've heard differing opinions on this, but would like to save the $ and performance of the i if I can. Second, I drove the G35 and was impressed in its relatively much stronger engine and overall value proposition. I would be interested in hearing opinions from those of you out there who are more in the know.