I think the thickness of the aluminum is fine. I think the problem shrimpy had with them is.. he spent $1500 on a sweet a-arm setup. and this is the "Thanks" he gets for "custom" a-arm guards
I think 2mm would be fine, if it wasn't just flat, some turnup on it would stiffen it up a bit. For the money, I would expect something that could withstand a moderate rock hit. Even if the plate did withstand it, those 'clamps' probably wouldn't. Yea, spending $1500, one would think, would get someone a little better status than 'screw'em if we can'.