I've learned in the last week as a result of posting questions about race wheels that aero-ness is far more important than weight. I think that the Zipp 404s and Specialized/HED3s are, according to Cobb, very similar in terms of aero-ness, so the only material difference is wheel weight. The heavier Specialized/HED3 wheel would hurt you a little if your race course has significant climbs. Aside from that there will be a negligible difference between the two wheels and your speed. Save the money.

If you race on the flats or small rolling hills, and you want to go slower, get the ZIPPs. Otherwise, stay with the aero H3s.

Save your money. Stick with the Tri-spokes.