I've been on 3 rides where someone's radiator was damaged, twice it looked like a rock hit...and the other had a small stick through it.
I've also seen a couple guards that looked like they took some substantial hits from something(assume rocks).
I originally didn't want to try a guard, as I thought the engine temperature may rise a few degrees from reduced airflow, but I have never noticed a difference on any bike.
I have RRG guards out of the UK on my '03 Gsxr1k, and they fit perfectly and are very well made.
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