Is it OK to drive at high revs in low gears often?

I've got a fairly mediocre 2008 Subaru Legacy Outback base model. Sometimes I like to drive in the range of 4000 to 6000 RPM before shifting. (It redlines at 6250 RPM.) So will it kill my engine if, say, I'm driving at 4000 RPM and I suddonly floor it up to 6k before shifting up?