Perhaps the benefits of cross drilled discs are more apparent on the road than on the track? Slightly lighter and better response in the wet?
Looking at race cars (ie GT3 R/RS), you don' t see many cross drilled discs. Slotted discs are more common. More relevant for us, look at the SCs and now 3.2s in the Porsche Classic series - I can' t recall seeing any drilled discs here either. Maybe the rules don' t allow it (?).
As a data point, I had a friend who raced his 930 for years (still does). His OE drilled discs all developed cracks around the holes. He just accepted it as reasonable wear and tear and would bin them when the cracks or the thickness became an issue. 930 discs are much thicker and have cast-in rather than drilled holes compared with 3.2 discs - so the problem may be more apparent on 3.2s.
Richard
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