Well, I'm 55 and my speed days are just beginning! I have a highracer and several lowracers. Ya know, 67-year old Bill Hannon took 3rd in the Avita Water Black Bear ride this year, going sub-4 hours for the 100 miles. He was on a Lightning F-40. I may try the full 100 next year, but I'm generally better on half-centuries or metrics. This year I did the ride as part of a 2-man relay, and I averaged 25 mph for my half.

My advice is that if you want a bent that performs similarly to a roadie bike, then get a highracer. A Bacchetta Corsa is good bang-for-the-buck. The RANS F5 Pro looks good, too. If you're willing to spend more, look at highracers with carbon frames. The ride is fantastic, and they're faster than stink.