I have a Fuji Outland 2.0 that I bought on ebay. It comes with an Ario R shock that doesnt have a lock option.
Im planning on buying a new shock, and should be a 200mm eye-to-eye. But seems like the 216 shocks are way cheaper (second hand).
If I install one of those, would it work correctly? or will I notice any disadvantage like stability or something? I mean, will I have any cons I should know about?
Take off the 200mm shock, measure what - if any - extension there is to be had with the suspension cycling free. What you want to look for is whatever link is driving the shock, how much more it extends after it's 200mm design to be at rest.
If there is .62" (16mm) of excess room up in there, the shock bolts up then. The suspension is not designed to be utilizing this free-range of travel and likely will create spikes in the rebound, the compression or, both.
Stuffing the shock into this space even with exactly .62" extra of shock-stroke (which is not available) will not have the top-out matching the full stroke of the suspension.
As a rule, you can go shorter with shock length. Going longer by over 1/2 inch is not met with good results.
Putting a longer shock on will also make your head and seat angles steeper, which could mess up the steering etc. The other issue could be that you may now have too much travel at the rear wheel, which means it could hit the seat post or other parts of your frame at full compression, which is generally not very desirable. As mentioned above, going shorter causes less issues than going longer.