fastrac has my vote
as blue 99 srx says , i am the studmaster! { i installed on our last 5 sleds } hers and mine! best deals at haydays ,fastrac has a booth, they do deals , have all selections there, blue 99 srx , has a ski poo now and her studs were stud boy for single ply but because she wanted yellow round backers we took sample over to the guys at fastrac and the fixed us right up, we both run the round plastic backers on all (5) sleds ,red, white, blue, black and yellow colors and have never had an issue, but as the guys at fastrac showed us, the design of the shoulder were the backer sits and the head fit, are different from stud to stud !!! all studs are not created equal! LOL! PS: i really like their studs because they dont rust after install, not like some other brands ! fasttractraction.com