first thing is superatv.com is the best place to get them.
next if your not going to at least 28" tires you dont need it. 26 and 27 inch tire wont rub the fenders at full suspension compression.
now yes rear axle on the SRA you wont gain any clearance with stock size tires. and you only gain .5 inch for every inch taller.
also if your looking at putting 28" or taller tires on it. you have to watch out for minor rubbing. using 1 or 1.5" spacers help with stock wheels. also with stock or aftermarket wheel the wheel spacers give much better handling by placing the wheel out witch this helps in deep rutted trails by getting your machine up and out of the ruts so your rear housing doesnt drag in the center. hope this helps. you out.