At a rough guess, and based on recent Velonews tests:

• Going from 32-spoke standard-depth wheels with 25c clinchers, to carbon fiber aero wheels with fewer spokes and 21c tubulars will gain you 10-20 watts, and may also handle weird in stiff cross-winds. Aero wheels could cost you $700+ more than standard wheels.

• Going from a round-tube framed bike to a top of the line aero bike will save you 10-20 watts. Cost varies, but could be only a $500 difference.

More to the point, though, you don't need a Venge, or SRAM Red, or Zipp 404's or a 13-pound bike for training and higher-speed recreational rides.

If I were in your shoes, and keeping in mind there's no way I would drop $7000 on a bicycle .... I'd go for the Tarmac Race Rival ($3000, around 17 lbs, nice color scheme). Throw a pair of Psimet or similar aero wheels ($1000), and you'll be in only a few watts and ounces shy of what you'd get building up your own Tarmac with Red and Zipp 404's.