Shut up Josh if you don't know what you going on about.
The difference, if you had already guessed in lenth. The longer the crank, the lighter the gear ratio. I am using 170 trialtechs, from going from 160 onza t-pro cranks. And it rides so much better, everything feels bigger, yet easyer. I personly wouldn't recommend anymore than 170's on a mod as it would feel too light, and feel like shite!. (In my opinion) I think slutbikes Adam uses 175's and he seems to be getting on fine with them.
So, It's more personal preference. But I recommend, go for it.