When i bought my 680 new it had 25 inch mud lites which where ok. Until i compaired how much lighter the zilas are. Then i went upto a 28 inch zilas because it was added so little weight but i gained an 1.5 of ground clearance + 2.5 inches from the lift kit. 4 inches of added ground clearance mad a huge difference.
Now that i have a gear reduction i'm running 30 -11- 14 zilas all the way around I know have 5 inchs more ground clearance then stock. It has helped alot not just in the mud but over larger rocks and logs.