450r shocks on a EX are better than stock for jumping but raise the ride hight.
On tests stock yfz450 against the 450r, the yfz shocks were called better for mx. Thats was the shocks on on the original quads their made for but still the yfz shocks are better for mx than 450r.

I would pic yfz450 shocks over the 450r shocks any day. Why? Cause they are better for jumping and mx type stuff and thats what i do.
If your a trail rider than you dont need 450r shocks cause it will only make it a ruffer ride. Trail 400ex stockers are good.

If you trail ride a lot but like to hit the track some times or hit jumps get the 450r shocks But, if your not bottoming the stock 400ex shocks all the time then why get 450r shocks?

450r shocks are slightly longer eye to eye and offer only .2 more travle over stock. They raise the ride hight around a inch. They get hotter faster than yfz shocks.

Yfz450 shocks on a Ex allow you to adj the ride hight up to about stock hight or you can adj the hight all the way down to about 5" lower than stock hight which is mx hight. They are said to be more adjustable. Buy that i mean that turning the dials is said to be felt more on the yfz shocks. Im not sure about that but my compression/rebound adj just a couple clicks can be felt allot.
The shocks offer about 1 more inch travle over stock(9.1).

I checked the bottoming points.
When a 400ex with stock shocks bottoms the A-arms are about streight and would be about teh same using 450r shocks.

When a 400ex with yfz450 shocks bottom it bottoms just at the right time. Stock A-arms can only pivot up so far b4 the ball joints go to their limit and at that limit the A-arms will stop moving. Well with the yfz shocks the front bottoms just b4 the ball joints come to their limit. Like just right. If the shocks could compress like a half inch more it would bottom out on the ball joints and that would break them realy easy. So they allow your shocks to compress as far as possable with out breaking the ball joints.
Yfz shocks are said to be valved for +2 A-arms from the factory.

I put the ride hight as low as it could go and i was hitting doubles. The front shocks would almost bottom every time i hit the double but wouldn't. Once the shocks started heating up i noticed i was bottoming lightly. It didnt feel like it, it felt like a soft landing but i saw marks on the ground so the front of the frame was scraping the ground some times when the shocks bottomed. It never bottomed hard one time like the ex shocks would do. It only bottomed very lightly.
When i have it on the lowest ride hight i put the compression on teh second stiffest setting and have the rebound all the way out at less their isn't many jumps.

If you put the yfz shocks as soft as they go they feal to soft. When i had them as soft as they go it had to much body roll which means to soft which means they can go from stiff were they dont move to soft probably softer than 450r. Actually on the softest setting they felt almost like the stock 400ex shocks just not as springy.

you can adj the shocks so they never bottom.

Over all i would say yfz shocks are the better choice.

yfz stock shocks on stock A-arms (shocks look differant but are stock)