Originally Posted by silvia tech

Actually, the 2007 base model sentra has the MR20DE motor in it same as the versa. The motor has lengthened conrods and an offset crank to help response, fuel economy, and stress of the internal components. The SER and SER specV have the QR25DE motor in them with a different set of rings. Nissan North America will not get rid of the QR25DE motor. 2 years ago they switched piston ring manufacturers. Long story short the new manufacturer failed to mention in their way of producing said rings the gap is different and the bore needed to be changed. As you know Nissan has lost Billions in the replacement of these motors due to oil consumption. The new QR's are not as bad as previous models. The only changeup in the production line for motors in 2007-2008 is the new twin intake VQ motor in the 350, 2008 pathfinder possibly frontier will have the V8 Titan motor in them and wilol carry a heavier pricetag respectively. As of now there is no talk of a mid-small car with a RWD configuration. Nissan is attempting to further push sales in the crossover area with the release of the Rogue which will have intelligent cruise control, aim adjust headlights and other intruiging features.