If it's durability you want, I would encourage you not to do this. More aluminum doesn't necessarily mean more durability. Most aluminum parts have no flex to them, and they do not absorb the shock of impacts very well. They will transfer that shock to whatever plastic components remain in your vehicle. You're just moving the points of failure to other parts of the vehicle.
It's a lot cheaper and easier to stick with plastic composite material for components like A-arms, body post mounts, bumpers, etc. It's better that they break first, rather than bigger and more expensive components like shocks, bulkheads, and chassis.
On the other hand, if you're just looking to bling out your ride, go for it.