My first mod was heated grips and a lead for a heated vest.
Yes I live in CA but I live in northern CA on the coast. The winter commute at 6:00 in the morning is in the mid 20's F to mid 30's F with a windchill factor of 55+ mph. After discovering the joy of heated grips a few years ago I have sworn that I will never own a bike that doesn't have heated grips