You're polishing a turd. The money you spend on the upgrade, you can get yourself a nice tiagra level bike. 2300 is as entry level as it gets without going to a dept store. No point in upgrading it. If you're set on this bike, just ride the crap out of it, and when you're ready, then find a more race ready bike. But seriously, an ultegra level crank is like half the price of that bike. I'd rather have an overall upgrade, than just one kickass part.