Alluminium bb and headset

I have the sizes and types. Semi integrated hs and cartridge bb, both vp components. Just that both have two versions, a cheaper steel and more expensive alluminium. My frame is alluminium with fork steel. Weight difference might be not that big, but in terms of durability and compatibility I was wondering if there was any advise. Cheers.

The only thing I can think of is that far far far in the future if you leave it outside for an entire winter or something the steel will rust a bit.

Hope you aren't paying too much for them.

http://www.chainreactioncycles.com/vp-zero-stack-threadless-headset/rp-prod108121