The std pipes I got with mine are like rodney007's, no visable restriction at all, with them on (instead of the Tygas) it goes pretty well and held it's own in the fast group at Donington even with the airbox holes covered up as well (with gaffa tape, I got black flagged for noise with them uncovered ).

With an HRC card, modded airbox, race cans and the std (unrestricted) pipes on, the Fontyyy butt dyno guestimate would be around 55bhp but with better midrange than with the Tyga pipes.
It was probably a jet size or two too rich but as it was just for a day I didn't bother sorting it out.
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