Following an inquiry from F1 2010 title rival McLaren-Mercedes, Red Bull Racing was instructed by the FIA to alter part of its rear diffuser ahead of last weekend's Monaco Grand Prix - but the Milton Keynes-based squad's team principal Christian Horner has revealed the change made the car that is already the fastest in the field 'even better than before'.

According to German publication Auto Motor und Sport, McLaren engineering director Paddy Lowe alerted the sport's governing body to an element of the diffuser on the Adrian Newey-designed RB6 not in adherence with the regulations. The car has been the subject of considerable scrutiny by fellow teams of late due to its crushing superiority, particularly in qualifying - with six pole positions out of six thus far this season.

Having acquiesced with the FIA's demands, meanwhile, pole-sitter Mark Webber and team-mate Sebastian Vettel still went on to thoroughly dominate the race around the narrow, tortuous streets of the glamorous Principality - in the process securing RBR its second commanding one-two of the campaign.

"Obviously the backs of the cars are so sensitive now we try and make it as difficult for others to see as possible," remarked the energy drinks-backed outfit's team principal Christian Horner. "We had to run a version without those [diffuser] wings, and found that it was even better than before."