"Bulletproofing" a Chrysler 2.7, 3.2 or 3.5 liter V6?

I drove an '06 Magnum with the 3.5L for 267,000 miles with nothing other than regular oil changes. I sold the car 5 years ago, and the guy that bought it is still driving it. I think that 3.5 was a great engine, and had good power and was reliable.