Hey Otherworld - the GSW head guards work great with the OEM BMW crashbars, although they will lightly touch the removable rubber piece on the inside of the bar. You can either leave it as is, or unscrew that piece from the crashbar for extra clearance. We've had customers do both, and it's pretty much a matter of preference.
Just FYI - I had originally thought the guards were going to be 4MM material thickness, but it proved too difficult to work with when prototyping. The production guards are 3MM aluminum...same level of protection as the others on the market. I must've missed the post you copied, but have since found and corrected the spec.
If you don't have crashbars yet, the DS Bike head guards work very well with the new stainless steel crashbars they've just released, as seen here
We have them in both natural bead blasted stainless and powdercoated black stainless, and they both look awesome. At $270 for a set of stainless steel GSW crashbars, it's tough to beat!
DS Bike is working on a raidbox application for the LC, although it will be based on aftermarket racks (SW-MOTECH, Holan, GIVI, Touratech, etc.). I would also expect they will have an application for the new LC Adventure when it comes available. The raidboxes (even with the new silicone door gasket) are probably best considered water resistant versus waterproof....they do a nice job of keeping the worst of it out, but some moisture still can get in there. If you want to ensure things stay 100% dry (tools, air pumps, etc.), we recommend putting the contents in a storage size Ziploc bag for peace of mind. We've thought about having some Cordura inner bags made up (and still may at some point), but at a cost of pennies the Ziploc solution is one even a KLR owner can love.
For reference, shipping weight on the oil cooled GSA raidbox is right around 2.5 pounds.
The GSW cylinder head guards (wrapped in bubble wrap from the factory, and with all hardware to install) weigh right around 1.25 pounds for the pair.
Hope that helps...any other questions, please let me know.