By model, quality split between best and worst razor thin

When it comes to out-of-the-showroom car and light truck quality, there is parity at the top and parity at the bottom. Overall, new vehicle quality slipped slightly among all brands for 2010, J.D. Power and Associates said last week.

Among all brands for 2010, the best -- Porsche -- and the worst -- Land Rover -- are separated by less than 1 problem per model.

But what about individual models? How do they compare? When it comes to measuring problems in the first 90 days of ownership, the gap is still wider between the best and worst model.

The Lexus LS sedan was the top vehicle for 2010 -- with just 55 problems reported per 100 model. It has held that honor for 8 of the last 10 years.

At the bottom, the worst 2010 model produced 199 problems per 100 models surveyed. That is less than 2 problems per model. But it's a setback from 2009, when the worst model produced 1.81 problems per vehicle. Still, it is the second year in a row that the worst model has produced, on average, less than 2 problems per model.

While J.D. Power won't disclose the worst model, it will reveal that the models have been different each year since 2006, with 4 different automakers represented, including domestic, Asian and European brands.

That's parity.