Comes down to the electronics you install in your car. I saved a bit of weight by removing any excess wire and heavy gauge (battery terminal wire). I ended up using a little thicker gauge than my motor wires. Servo plays an important role in the weight game. I had a futaba and switched it out for a sanwa and saved 7~10 grams. Motor brand makes a difference, battery, and esc.

*remove that chunk of lead weight (7 grams?) and put your receiver there.