as for them being an upgrade no they are not they are 100% the exact same m3's have had cross drilled discs of that type and size since they came out (51 plates iirc) they always have done throughout their production lifespan the only chassis options offered from the factory where EDC electronic damping force control and a choice of the multi spoke 18's or the more commonly seen polished face 19's that you see on the vast majority of them then obv. the BBS wheels that the csl and cs came with
what i'm saying is that the only reason the times for the csl are only that much quicker are most likely down to the driver having to factor in some quite excessive brake fade
Just to prove that the expert is wrong again, below is taken straight from wikipedia and highlighted in bold is the upgraded brake specification:
M3 Competition Package
While it is known as the M3 Competition Package in the US and mainland Europe, it is also known as the M3 CS (Club Sport) in the UK.
19-inch BBS spin-cast (flow formed) alloy wheels (marketed as "forged"); 19"x8"front, 19"x9.5"rear: weigh 26 lb (12 kg).
Specially tuned spring rates for the Competition Package; this was carried over to all M3 production from 12/04 on.
CSL steering rack: More direct steering ratio of 14.5:1 (vs. standard M3's 15.4:1)
CSL's M-Track Mode DSC with a button mounted on the steering wheel (deletion of cruise control and steering wheel mounted radio/phone controls)
CSL's Compound cross-drilled rotors; larger front rotor of 13.6 inches (from 12.6 inches) with black painted calipers
Alcantara steering wheel, gear lever and hand brake
Interlagos Blue exterior paint available as an exclusive color option.
Unique cube aluminum interior trim
At the end of the day if you are trying to argue that an m3 Csl brakes will fade that quickly even tho they are cross-drilled large rotors. When you compare them to the far smaller and not even
cross-drilled standard rotors on the s2000 can you not even realise that they will fade the same if not more than the CSL brakes
Why cant people just accept the simple facts