IIRC that 'mod' was to comply with rules where the tire sidewall was not to protrude out past the top of the wheelarch & might have been due to a change of tire make/sidewall design, The MKII's also had a redesign in the wheel arch area after the daytona meet to give more tire clearance when they found the suspension loads on the banking compressed the ride height further than intended, one good pic shows the burnt paint/glassfiber in the area concerned.