Board Thread:Game Discussion/@comment-25956839-20150529184006/@comment-26444763-20150530130238

Once you get Endurance Kings unlocked, the way I got to the 10 lappers was the Audi R18 for R$. (If you didn't win the Porsche 919 or Toyota TS040 elswhere). It will cost you an additional R$2,583,600 and 335Gold to upgrade it to PR94. This was enough for me get the 10 lappers unlocked, happy days :)

BTW, I unlocked Endurance Kings with the purchase of the Porsche 911 RSR [2014] on special.