The '04 is indeed a PD engine. My parents have had one for almost 4 years now. They run the correct oil and the only problems they have had were with the crank trigger sensor and the HVAC system. Both of which got covered under warranty.The PD seems to have a bit less of the diesely clack clack noise that we all love... especially once warmed up. Compared to an ALH I would say the emissions are a bit better and fuel economy is a bit worse. Stock engine for stock engine the PD definitely has a bit more grunt.I think it's all about finding the right car that somebody has taken care of.