The Mag Hytec stuff is very nice. But you have to ask yourself what your goals are with replacing the cover. The MH gets you easier fluid drains, and some added cooling benefit, as well as extra capacity at least on the trans pan - how much cooling benefit is anyone's guess; maybe they've published some numbers on their site.
One thing that does concern me is that they are cast aluminum. If you're doing offroading (which I'm not and obviously sewlow isn't either) and crease the cover against a rock or other hard surface, it could break it. Seems especially a possibility with the transmission pan. A factory steel pan will get dented or possibly punctured depending on circumstances, but that cast aluminum has zero give. Don't get me wrong; I'm sure they are strong pans but materials can only be abused so much; something that might dent a steel pan and still let you get home, will leave you walking with a broken aluminum one.
Richard