Very important note. To anyone using the E4JS chassis and needs it to fit a 10" wheelbase body, such as the Vintage Trans Am HPI bodies. You will need to trim 3 mm off the front of the rear a-arm and put 3 mm worth of spacers on the back to slide the whole arm forward. You will also need to move both carrier shims to the rear of the carrier to move it towards the front end. This is 3.5 mm worth of movement.

HPI body wheelbase 255 mm.
E4JS wheelbase 259 mm.

My rear wheels are perfectly centered and my fronts are ever so slightly forward in the wheel well. Hope this helps too.