Is yours an STI? I suspect that it could be something to do with the AVCS (the variable valve timing) on the STI engines. I've heard 2 other friend's STI's, and they both have the same quality of noise. Not as loud though, but maybe its cos their milage's are higher. My engine's only at 4000km.

What's your milage at the moment?

 

Oops, posted wrongly. The above should go onto my previous thread.
Apologies.