| Who am I to comment as my 996 has a 54mm but my 998 only has a 50mm system. My 955 also has a 54mm system with the 748 that i'm building having a 45/50mm set up. They all look and sound good and with the right chip matched to them they all perform well.
My 916 only ever had a 45mm system with carbon Termis and a Senna Chip, it made a tad over 104bhp on the MotoRapido Dyno and not only sounded sweet but went very well on the roads and track | 
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