What else would I need tochange my Earthquake 8e to aBackdraft 8e other than wheels,17 mm hubs, body posts? They are very simalar right? as well as the Aftershock 8e. I was thinking of doing this beacause while this truck is a blast I think that the tires are just to much for the diff gears so I want to change up and make it last and be a bit more stable.

You will need to change the bumpers and rear wing mount - thats it. Then you can use any 17mm 1/8th buggy wheels as well.
Here are the part numbers
bs903-009 front bumper
bs701-031 rear wing mount
bs701-032 rollcage post set
bs701-033 front body mount
bs701-034 rear body mount
bs803-003c clear buggy body
mpo-01 17mm wheel hex kit

Hope this helps [8D]