[BoxsterBob - CA]

The flat six design of the boxer engine can allow a small amount of oil to seep past the rings into the combustion chamber when sitting, resulting in the white puff. Unlike the V-6 design that has gravity in its favor. This is normal. If the smoke continues beyond the occasional puff, you may have a problem, anything from Air Oil Separator (minor) to porous cylinders (major). The occasional "belch" on start, while embarrassing, is normal.