Ford has sold out of its 101 unit allocation of the £35,450 special edition Focus RS500 in seven days.

The RS500 had five times more customers than cars were available and as a result of the high, Ford is launching an engine upgrade kit for existing Focus RS customers that want to boost the power of their car.

The Mountune Performance (MP) 350 RS upgrade kit is £1,995 and adds an extra 43bhp and 20Nm of torque.