Originally Posted by
nemeseri
Not necessarily. The most important thing is that you have a nice and comfortable fit on that bike. A race geometry will only gain you time if you can use the lower stack. Meaning you can handle larger saddle to bar drop. What's your current drop? Do you want to be more aero? Can your back handle the more drop?
I wouldn't buy a race geo bike just to put 3cm spacers and +17 degree stem on it.
I think both bike you mentioned are exceptionally good. I'd choose between the two based on riding them.
How am I really going to know if I can handle the more aggressive position without owning it and forcing myself to ride several hundred miles with it to see? Even my Synapse took a little getting used to coming from a mountain bike. Believe me that I hope that I'm not getting into a more aggressive geometry that I will hate and not be able to endure for six hours on a century ride.