XRAY - Model racing cars

Im reading posts on rctech talking about not running either front or rear top decks for my traction is that correct and what would be the advantages

There was a mistake in the basic set-up sheet saying to not run either of top decks. However, this mistake has been corrected as you have to run at least the front top deck, where also the body holder is attached. Not runing the rear top deck gives you more flex.