I run royal purple, have for years, probably about 8 years in every vehicle I've had. Depending on how I'm driving it I go 8-10k miles before changing it. If I drive like a maniac its more like 4k lol. I recommend changing regularly, but if you know your car you can feel when it needs it.
Before you run it you need to use one of the many engine oil flushes made. Lucas and castrol both make good ones, it will clean most the sludge out.
