well the most common are the 85-86 ones and then you can get the trx 250r years 86-89 i believe and the trx ones are nicer cause there shorter than the atc ones by like 1 inch and the atc ones boost your rear end up like 3 inches so if you can get the trx 250r it would be better, a little bit shorter, about stock lenght but still way better than stock......i had an 85 atc shock on mine when i had it, loved it......was soooo soft and like riding on a cloud
they are also a hell of alot more money.. u think i shold get atc then get a better one once i have money cuz im looking for a good and cheap one right now