ID have to say gears, when i switched mine out was probably the best mod i ever did, to me i could feel more "seat of the pants power" then after my cam install, i know sounds crazy but 3.23 to 4.10s is an awesome jump
I did the same 3.23's to 4:10's.. I have to dissagree with you though bro. The best smile factor mod to date was my converter change! But I did that at the same time as my cam so could be comparing apples to oranges.