I have a 105 Topstone with an Omega FSA. I replaced it with an FSA AGX 46/30 with a new BB. I didn't go with the Shimano because the front derailer would not match so going with the FSA AGX was and is a drop-in and has worked perfectly. The crank was more expensive than the Shimano but it ended up less as I didn't have to change the front D.
Frank.
