Chip 4.2 without any another tuning is bad idea. You won't feel difference between stock car.
Install SCHRICK camshafts with chip.
AUDI V8 (AUDI S4 2003-)
457 E1 641-L0
457 E1 641-R0
457 A1 721-L0
457 A1 721-R0 http://www.drschrick.de/english/index.php
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