I posted a while ago how close all these cars are regarding mechanical breakdown costs. When we "underwrite" and extended service contract, we know what the losses will be based on the data from a very large pool.

Some rough examples of cost on a "bumper to bumper" style, 100,000 miles warranty:

Accord/Camry - $1100
Ford Taurus/500 - $1100
Ford Explorer/Chevy Trailblazer - $1400
BMW 5 Series/Cadillac/Lexus - $2200

Luxury cars get a little more pricey ... but even the difference in domestic sedans to their Japanes counterparts is neglible.