wrote:

I am looking to spend a significant amount on a new road bike in a
couple of months ( US$5000). I was considering a high-end carbon or
titanium frame stock model with top-of-the-line Shimano or Campy
components, but now I am wondering if this is the best approach.

At my body weight and riding style (day-touring, NO racing), I doubt
that a couple of extra pounds on the bike would make a big difference.

More importantly, a couple of extra thousand dollars on the bike won't
make a big difference.

Actually that's not precisely true. As another poster said here, those
extra thousands of dollares are more likely to buy you early failure or
at least continual hassle. Conversely, those couple of extra pounds on
the bike are more likely to buy you a reliable, durable machine.

These are not absolute rules but just rough guidelines. The worst
offenders are boutique wheelsets vs. traditional wheels.


Do the second-best
components from say, Shimano (Ultegra) differ from the top-of-the-lie
(Dura-Ace) only in weight, or is there some other advantage to the
Dura-Ace?

Sometimes or perhaps often the "second-best" are better for your use,
withness the Dura-Ace bottom bracket fiasco of a few years back (poor
seals). The high end sometimes has titanium or aluminum or carbon fibre
where you don't want it. Again, not absolute rules but just guidelines.

If you look at the highest-end "custom standard" touring machines more
often than not the builder specifies them with Centaur or Ultegra or
similar.

,