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I forgot - the new Jeep Wranger with the 2.0L Turbo also has cooled EGR. Cooled EGR's role on spark-ignition gasoline engines is different from diesels. For gasoline engines, it serves two roles - reducing part load pumping losses (run more EGR and use less throttle) and knock or preignition mitigation (more of an impact on the turbo applications). It's not easy to do on gasoline engines. High EGR rates can slow down combustion to the point that combustion phasing can be less than ideal. It can also be difficult to ignite. Engines using cooled EGR usually have higher energy or multiple strike ignitions systems and intake ports that do a better job of inducing tumble. Having a lower bore-to-stroke ratio helps generate turbulence, too - increases port velocities for a given engine displacement. Check out the relatively long stroke on the new Toyota I4 engines.
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