Here is the dependability study:
http://www.jdpower.com/news/releases...04055&search=1
Top 3 are Lexus, Buick, Infiniti as of 6-29-04.
The time frame is # of problems over 3 years.
I would not worry too much about severity as that data is likely more difficult to capture and highly correlated with number of problems in many ways...
...in fact maybe the best way is to look at residual values for a financial market assessment of vehicle quality.