I've had my BSM E90 for 2 1/2 years and I've introduced ZERO swirls by using the techniques I learned on this forum.
I agree with most of the posters:
- the swirls might have been there from delivery
- rinse the wash mitt frequently, especially when washing the sides and back
- use MINIMAL PRESSURE while washing and drying
- use top quality cotton or MF drying cloths
I've been pleased to learn that BSM doesn't require perfect technique. The paint seems to be quite hard. So there seems to be a LITTLE room for imperfect technique.