Someone somewhere on one of the three MS3 forums posted a link to a $20 prefilter for the AEM CAI filter. Unfortunately I did not save the info and can't find it using the search.
you mean the injen water repellant pre-filter? well here is the one from su http://www.***************/Injen_Water_Repellant_Pre_Filter_p/x-1033.htm
for 29.99 and if your concern was it being 10 bucks cheaper su is always free shipping so it would always come out to be the same in other places. i have one on my speed6 and its great. keeps my aem cold air intake filter clean from all the crap kicking up on rainy days
well i have an aem cold air intake on my speed 6 and i am using it now. i have the dry flow air filter and it fits perfectly. i dont see why it wouldnt work on the speed 3's filter made by aem . i would assume they are identical. if i am wrong sorry. maybe a call to su tomm morning would answer your question