I cant comment on the A arms....My first guess is they are different?
The M series skid went right in 03 Mtn Cat, but the PO had Holz rear drop brackets installed, So I did not need to change the rear drop bracket.
You will need the 1/2 spacer up front! Night and day difference!
pick up a set of 16" ctc floats...couple guys partin out kingcats that might have them. If you are interested I have a 2010 153 float skid....as stated before, you are going to need drop brackets for the rear. And yes, you will need 1/2" spaces on all 4 corners.