I ride a lot of centuries and occasional doubles with some pretty fast riders (cruising speeds on flats are usually well above 20 mph and are often around 25 at times). My long rides are often still hammer fests, so I still have to have a fast bike even if it also has to be comfortable.
I don't have a dedicated distance bike so I usually just use my aluminum TCR0 (full on race bike) with a few extra headset spacers, double wrapped bars, 25c tires and a Selle Italia Pro-link Gel Flow saddle. This set up seems to serve me very well giving me comfort and speed at the same time and the TCR frame has been a hard one to give up for me. . I actually have a great chance to buy a Specialized Tarmac SL frame for little $ but am thinking that might be a little too fragile for a good double-century-in-the-middle-of-nowhere bike.
I dream of dedicated "comfort" or "distance" bikes like the Independent Fab. Club Racer, Gunnar Sport, or Salsa Pistola. But I am not really sure I will see any difference in comfort and am afraid that I might actually see a decrease in stiffness, speed, reaction time, etc.
When I look at "comfort" bikes, the biggest differences seem to usually be a shorter top tube and taller head tube. I can get the same result of both of those from a stem swap out.
So what am I missing? What are the guys who ride fast LD rides buying? I am more than receptive to an excuse to buy a new fast LD bike but I am just not sure that I can get anything with a more optimal mix than what I already have.
Who has fast LD bikes and what do you love about them relative to the option of "comfortizing" a racer.