You'll loose a bit of low end torque, get a slight increase in top end, and a different noise (when I did I lost the growl at low rpm for a slight increase of sound at higv rpm, but did not get a better sound)
But if you think about it, you spend more time between 1800 and 3000 than above 4500, so it won't benefit you everyday!
If you can do it for cheap, do it, you'll see for yourself if you like it
It won't light the CEL or make the car run rough.
Ben