RE: anything i can do to widen my rustler?
monty is right, widening would make it worse. I widened my pede and it worsened matters, I will never widen a vehicle again, especially with wheel extensions.
If you need more stability at higher speeds. Try using 2.2 tires, more shock dampening, and lowering the vehicle. I think these 3 things will get you going a bit better at high speeds.
You can use 4tec axle carriers on your rear which will give you 1.5 degrees toe in, this could help but am not sure. Maybe a street guy could elaborate on toe and camber for on road traction.