Hello, I have a 2007 Cannondale CAAD8 Optimo2 and interested in changing out the stock Tiagra triple(30/39/50) crankset. I know this may be some kind of sin, but I was offered a NEW Bontrager Race Lite, 9 spd, w- Truv Giga X Pipe BB, 52-42-30 for $100. I believe it's a 68mm shell and something like 118.5mm spindle length. Would this fit/work? I don't have the tools to make the change, so would be purchasing and taking to a shop to change.
Lastly, Is it worth to make this change (smother, better quality, lighter, etc)? I have put nearly 4,000 miles (including century rides) on the stock Tiagra crankset and has done very well. But always looking for good upgrades.