▁relatively ▁open - ended ▁and ▁with ▁room ▁for ▁innov ation , ▁leading ▁to ▁a ▁huge ▁variation ▁in ▁how ▁the ▁cars ▁look . ▁There ▁is ▁a ▁k it ▁car ▁available ▁to ▁allow ▁a ▁simplified ▁entry . ▁ ▁Up ▁to ▁ 2 0 1 3 , ▁F 2 4 ▁races ▁consisted ▁of ▁a ▁ 4 - hour ▁end urance ▁race , ▁and ▁teams ▁could ▁use ▁six ▁batter ies ▁in ▁that ▁time ▁( 8 0 ▁minutes ▁per ▁pair ▁of ▁batter ies ). ▁A ▁minimum ▁of ▁five ▁drivers ▁were ▁required ▁to ▁drive ▁for ▁a ▁maximum ▁of ▁ 9 0 ▁minutes ▁each . ▁Typ ical ▁average ▁spe eds ▁were ▁around ▁ 2 0 - 3 0   m ph . ▁ ▁However , ▁the ▁rules ▁were ▁modified ▁for ▁the ▁ 2 0 1 4 ▁season ▁to ▁change ▁the ▁F 2 4 ▁race ▁into ▁a ▁s print ▁style ▁event . ▁Teams ▁are ▁only ▁allowed ▁to ▁use ▁one ▁pair ▁of ▁batter ies ▁per ▁ 9 0 ▁minute ▁race , ▁with ▁two ▁races ▁during ▁the ▁day . ▁There ▁must ▁be ▁a ▁minimum ▁of ▁three ▁drivers ▁per ▁race . ▁ ▁Pr ices ▁cover ▁a ▁wide ▁range ▁as ▁different ▁teams ▁use ▁different ▁designs , ▁materials ▁and ▁techniques . ▁The ▁highest ▁cost ing ▁car ▁doesn ' t ▁necessarily ▁give ▁the ▁best ▁results . ▁Top ▁cars ▁have ▁r anged ▁from ▁the ▁price ▁of ▁£ 1 2 0 0 ▁( ex cluding ▁batter ies ▁and ▁motor ) ▁up ▁to ▁approximately ▁£ 9 0 0 0 . ▁The ▁motor ▁and ▁six ▁batter ies ▁cost ▁a ▁total ▁of