There are so many things wrong with this post.
First off, the lower mounts on Fortune Auto Coilovers are Steel...
Second, both Fortune Auto and Megan (and just about every other Coilover Manufacturer) use Aluminum (usually 6061-T6) for the upper mount. If you look at the loading on the upper coilover mount, you'll see that if you've gotten the 6061 to yield, odds are, you've got a MUCH bigger problem on your hands than a broken coilover.
Third, when looking at impacts, specifically wheel to curb/other impacts, you want to look at your suspension system as a whole. If you hit a curb, what do you want to fail? An expensive part? A cheap part? Do you want something to bend instead of breaking so that it protects everything else? Usually, the last option is the case... So, let's say you do hit a curb, and the lower coil mount were to snap. This means that it snaps and should protect the rest of the coil over from breaking.... Or you could have a super mega strong lower mount, which is just going to transfer forces into something else until it breaks...
Also, FWIW, just because something is Aluminum doesn't mean it's weak, and just because something is steel doesn't mean it's strong. There's much more that comes into play including the exact design of the part, the alloy of Metal Used etc.
Oh, and just a bonus for going with Fortunes or PBM's or someone like that is that you can upgrade the coils at a later date without a tonne of hassle. Fortune specifically markets this to their customers, as does PBM (stuff like the SLL Spring) but to a lesser extent. Buy Fortune coils now? Want to upgrade the springs later? Or have the struts revalved? Or upgrade the bearings? You can do all of that without having to find a third party vendor.