Question about running weight for carpet??

[J.Gonzalez]

Getting back into offroad racing after rather long time (like a decade!) running electric and nitro onroad so I have a few basic questions.

In review of most of the setup sheets the car are around 1550-1600 grams running weight for carpet racing.

Now I checked my car with nothing special or light weight and it was 1450 with a 5000mh battery.

That is A TON of weight to add to the car to get to 1550-1600 range

Am I missing something or is the high running weight required for effecient chassis?

Also setup mention shims under ball studs but dont give a size of shim...is it a standard size does any one have a reference.

Thanks
Jamie