I own a 2010, John Cooper Works convertible mini--6 speed manual transmission. 75,000 miles. Been running great, but it just started having a slight rattle/noise right when I start it up---seems to disappear once the engine warms up. Doesn't seem to affect anything from a performance perspective---any thoughts on what this could be ? I'm not a 'car guy', so I worry about getting 'sold' when I bring it in for service.