Well, that kit you have listed can't possibly have the late bearing in it or else that isn't the correct picture. For it to work like you said they told you it would have to have two inner bearings in the kit and the picture shows only one.
I'd be looking into whether the right bearing was installed or not or if they did like I said in the above post and installed the early bearing with the original late race.
Fortunately for me, my car came from the factory with 3.73's in it and covered under the warranty!
I am 80% sure what's in that picture is what was included in the box I received and brought to my installer. Is the picture showing the correct bearing?
Current Mods: 19x8.5 Charcoal AMR Rims, Bama Tune 93H, Airaid CAI, FRPP Sport Axle Backs, FRPP 3.73 gears, Boss/CS/GT500 Rear Diffuser, GT500 Rear Spoiler, GT500 Mud Guards, Raxiom Reverse/License LED Lights, OEM Take off Black Charcoal Leather, GT500 Steering Wheel, Auto Headlights, Chrome 3.7 Badges, Quarter Window Louvers, Dark Matter Tint
Future Mods: Matte black GT500 Stripe, Black Billet Grilles, Stillen Front Chin Spoiler, Roush Side Splitters, Painted Mirror Caps