Just read an article in fourwheeler about a diff-cover abuse test. The aluminum cover held up for a while but eventually cracked open. The abuse they put these covers through I'll probably not see, however the SSteel and cast iron covers survived, even the stock cover. I know the aluminum cover will keep it cooler, some claim 45deg or so (Mag-Hytec). But is that just from the aluminum? or also from increased capacity, and increased surface area (fins)? could a steel cover with increased capacity and cooling fins come close? If so I may fab one up. I just want to protect my investment, I will see highway speeds and some towing with my 14ff. thanks in advance.