On my 87 Warrior w/ 01 Raptor rear shock, I don't have a skid plate (other than factory), but I had to do a little grinding w/ a die grinder and a carbide bit where the spring just touched the swing arm. The outer diameter of the spring is just slightly larger than the stock Warrior spring, so I had to grind a couple crescent shaped areas about 1/4" deep in the upper part of the swing arm to clearance the shock spring. After that, everything worked fine.
I did find it was much easier to loosen the bolts on the air box and raise it up slightly while getting the shock into the right position. After the shocks in place the air box can be bolted back down.
I used the original reservoir holding clamps from the Warrior to hold the Raptor reservoir, but you have to remount it on the left side. I used a couple 10-24 bolts and nuts and drilled a couple holes through the plastic just below the seat and mounted the reservoir. It;s out of the way there, and it's so light it won't stress the plastic.
John