oh ya, and that elbow deal..I was able to cram a 2.5" on the stock AFM but it wasnt easy. 3.0" however is wayy to big so you kinda gotta make the 2,5 work. just spit on it and use a thin little flathead screwdriver or something to sorta work it on as you push down. two peaple will make it easier too.
so, the official size to go from the stock AFM to the TB is 3.5" - 2.5". now the other question at hand is whether to use a 90^ or a 45^ because the angle is somewhere in-between. I would say its closer to a 90 if anything. I imagine most of you guys running the stock afm dont still have it mounted in the origional location so that probably doesnt matter anyways.
there is one more issue at hand. the hose that comes off the factory elbow that goes to the idle control valve will have to be sourced from somewhere else. you could use the barbed fitting that the valve cover breather hose goes to and run that to the idle control valve. that hose needs to get vented to atmosphere anyways to so you dont boost the crankcase so that shouldn't be a problem anyways.
so price on the 3.5 - 2.5 90^ elbow is $29 shipped