Interesting Question. I assume 131's were used for Rallying Only. The European Touring Car Championship may be a source of further information.
I remember going to the Touring Cars (or some event) at Oulton Park in 1987 and the main cars were still Capri's and Rover SD1 Vitesse's of all things. In the same meeting there was an event called something like 'Slick 50 Budget Saloon Car Racing'. I remember an Orange 131 Sport in this that appeared to lack straightline speed in comparison to the Capri's and Rover's (In this event to)
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I remember seeing 130 TC's doing fairly well in production car events in the mid to late 80's, with the Touring Cars being dominated by Sierra. Never been to a car race since then as I discovered Motorbike Racing
(Spectator)