just how your weighing the car now, you say you got 1647 g ?
no body full tank , new tyres, i weighed my other car, converted G4+ to RS and it weighed 1595g.
my new car has lighter front axle, and all plastic pullies, so im dropping about another 12- 15g. so there is a difference to the parts used. as you know the chassis is about 20g lighter, 35g lighter than the G4+ 4mm chassis. lipo can drop another 20g and so on. this just allows weight to be added where the driver wants it.