I currently have the stock touro crank that came on my mercier kilo. I immediately upgraded the wheelset to Iro and I've put about 4000 miles on it since I bought it 10 months ago. The crankset has a lot of flex to it, but I don't have much money right now. So if I do upgrade, I can't spend much. Would an inexpensive crankset such as a sugino rd or a crankset from bulletproof be that much better than the touro crankset I have now. Also, because of mileage, which will likely last longer? Thanks for the advice.