G'Day,
I have one - got it once I'd put a deposit on my Sprint (after I discovered the cost of a replacement radiator!).
I believe it's aluminium but check the website
http://www.radguard.com.au/index.php?main_page=index
I got the kit including the "V" piece. Intallation took about 1.5 hrs, but that was also the first time I'd had to figure out how to remove the fairing.
Installation was relatively painless. Peace of mind is priceless! Inspecting the unit today, I note a number of small nicks in the guard - dunno whether any of these would have translated into damage to the radiator, but it's good to know it's doing it's job anyways.
Highly recommend it.
Cheers,
Neil