As long as it never under any conditions has any restriction you should be good to go. I run an oversized Uni in the airbox and another standard 5x4" in the inline can. Even without the Donaldson it took quite a long time before making restriction on my 800 but there were times..very dusty conditions.. when it did before one ride was over...let alone several days. I could tell when I was asking more then it could get so I kept it under 4K. Now with the Donaldson, I only have to service it every couple of trips and still one big one in the air box only needs it once a year..and that's just to get fresh oil treatment on it.