Are the wires the reason for the weight? Do bees buzz, do flies fly, do bears defecate in the woods? Er... GET RID OF THOSE WIRES!!!
Take it all off, and the brass terminals on the speedo if they'll come off, and replace it all with 16g wire in just the length needed to reach from speedo to motor and battery. This stuff is the dogs...
http://www.zen-racing.co.uk/catalog/...6g-wire-p-1188
...and comes in blue, red, orange and black so you can keep the colours if you want to. Leave a little slack on the motor wires so they don't interfere with free movement of the pod, and make the battery wires such that the negative won't reach the positive terminal - stops the release of the smoke capsules in the speedo when connecting in a hurry!
Body weight suggests you have a lightweight shell so that's good.
Did you balance the chassis to get rid of the one-sided wheel lift, or did you adjust the rear springs? If you did it all on the chassis balance that might still leave a tweak in the car. As a double-check, look at the rear spring nuts.
They should have about an equal amount of the bolt showing above them. When you lift the car by the chassis, the rear springs should have an almost equal amount of slack on each side. If these aren't even close then you have balanced the chassis, but not the spring pre-load and you will still get odd handling.
Here's a pic of my GT showing both the above. HTH
