Givi claims to the contrary, the engine guards fit a 2011 California model just fine. I got out my Dremel for the canister cover, but didn't need to use it.
Actually I installed the Kappa guards, which I think are Givi guards minus US$40 in price. Thanks, weljo2001 for posting the link to those on ebay
And as far as "fit just fine", I enhanced 3 of the holes with a drill. I added rubber below the frame clamps. One of the holes I enhanced was on a clamp, and probably wouldn't have been needed without the extra rubber. The other two were the left side guard bolt holes.
The main thing I've noticed is that traffic lights seem easier to trigger with the extra steel up there.
Of HB, SW Motech, and Givi/Kappa, these seemed like the lightest--based mostly on shipping cost from a vendor who sells all 3. I also thought they had a narrower profile than HB (which I think are the heaviest). Now that I have them on I'm not convinced they're much narrower. If you have HB, I'm curious what the tip to tip measurement is for those.
If someone wants that info about these I'll post it.