To the Irish muscleman. . .
The Specialized Allez and most performance road bikes have an extremely fragile, paper thin aluminum head tube.
This is combined with a whopping long stem extension.
You guessed it. Crack!
Should you decide on an aluminum bike, do replace the stem extension with about a 90mm or so.
This will make less leverage and less force upon the head tube where they usualy crack at the front, right above the brand name.
Second step, use 700c x 28mm tires. Speed is still strong at this size, but the additional cushion will further protect the frame from cracking. Ruffy Tuffy (Panaracer Pasela with or without Tourguard) tires excel that this speed and protection. Yes. They're flexible. It will save the bike.
However, a good steel road bike, in performance steel (not mass market steel) is just the thing for you.
Steel itself flexes instead of cracking. Bikes are available in exactly the same weight as aluminum. Steel at this very light weight range costs a bit more, but lasts many times longer.