Do you have any visible signs of leaks ? have you seriously checked over your car ? any deposits on your garage floor or parking spot ?
As for new engines, Coulter Nissan in Phoenix AZ is the first dealer in the US to replace an engine in this car. Call them and ask for Nick the service manager if you want to know about how that went. It was my car. As far as I'm concerned, good as new. In fact, I got 4 more hp on the dyno !
