aero rims on their own?
not sure – none of the deep section wheels we’ve had in this post so far are available as a rim only as far as i know, although with a bit of cajoling you might be able to get them as ‘spares’. If you can find them, and you build them up with good spokes, there’s no reason why they shouldn’t be comparable, but again i’m not sure you’d save much money.
on the question of the etape: do you stand to gain more with a heavier aero wheel, or with a lighter standard wheel? i don’t know the definitive answer, just askin’…