What is the distance between the center of the bottom bracket to the top of the seat on your current bike? If you have long leg/short torso @ 5’11", the seatpost might be too short on the Medium because the sizing chart shows a recommended seatpost extension of 300mm at 5’11" (though maybe you could get one of those M2Racer thingies). However, if you went with a shorter than recommended stem on the large, like 80 or 90, you would probably be just right (although handling might not be as great, that’s the compromise with your build and this bike). And if you were to replace the seatpost entirely with a non-setback seatpost (I don’t know if they make the reversible ones long enough for the Roadster) for a slightly steeper seat-tube angle and scooted forward on the seat for the race, you would have a better tri setup.
Regarding tubulars vs. clinchers, I think it’s safe to say that the advantages of tubulars are almost entirely limited to Euro pros that have spare wheels/bikes following them everywhere. The rest of us have to deal with the cost of tires, glueing (or fixing), waiting (for tires to stretch/dry etc.), fear of high-speed cornering, impracticality of daily use in exchange for knowing that the wheel/tire is lighter and stronger and the tire has a little bit less rolling resistance. The thinking behind this and every other expensive upgrade (like aero wheels) is that in a top professional competition, the top pros will all have nearly the same capacity/fitness so every percentage advantage counts in determining who wins. The best tire/wheel combo can often determine 1st or 2nd since the time differences tend to be much smaller at the higher levels of competition (and if one guy goes for something with a 1% advantage, everyone else is going to follow). At the lower levels, it doesn’t matter as much, but it’s always cool to have nice gear if you can afford it. There’s nothing wrong with working towards being worthy of the stuff you buy. Or buying new stuff to motivate yourself and keep you interested in the sport (maybe that’s a little wrong …).
I think the accepted benefit of aero wheels is something like a 5-10% time savings depending on the wheel and the tire. It’s good that you’re not hung up on all the “tech crap” because most people don’t recognize that there are much easier and cheaper ways to get an extra 10% by doing certain little things (which will be another thread)… but at higher and higher levels of performance, it becomes exponentially harder to get that extra percent of endurance or power and it becomes necessary (if you hope to win) to spend the big bucks and transform into aero-geek tech-nerd. Unfortunately, for a lot of athletes, it also becomes necessary to resort to illegal drugs, etc. (another thread). I think a lot of people who don’t have your great fitness level just want to invest in stuff that they can aspire to being worthy of.
Like you said, the triathlon you did was pretty small so there might not have been a lot of competition, but regardless, I think you’ll find that having nice stuff will be a great psychological boost because you have confidence that the quality (or cool factor) of your equipment isn’t limiting your performance. That’s why you’re getting the Roadster, right?
Admittedly, since triathlon isn’t just a bike TT, it makes sense that someone should concentrate on their overall fitness (because a great bike doesn’t necessarily make your run or your swim faster) before throwing down $200 for a 90g stem or $3100 for a Blade frame. But again, everything has its cool factor and everyone has their own spending priorities.
(now that I’ve written this rambling essay I can go to sleep)
Kelvin