Giant Defy 2 2012 BB replacement

rgrc28
rgrc28 Posts: 16
edited March 2013 in Workshop
Seeking help,
The bike currently has an FSA BB4000 MegaExo BB in it, which is on its way out (there's some play, is it going to explode on me, this is my comuting bike?!?)

Do i need to replace it with an identical model, or can i use a shimano 105/ultegra Hollowtech2 at less price and better quality?

I am not sure but i think the FSA has a narrower axle at 19mm and the HT2 is a 24mm axle, making them incompatible?

Anyone know for sure?