I think I read somewhere about the zippers beig bigger on the turbo. Here it is from activeendeavors.com:
The construction is like the classic version with triple interior compartments and an abundance of convenient pockets. But the Turbo has larger zippers, French piping, and a platform logo plate on the exterior.
OK I am so glad you posted that because I was wondering the same thing...and even with the stated differences, I really see nothing! Lol, maybe in person they'd be apparent? I think I'm going to order one soon.