The only potential benefit you will gain from leaving the lid off is noise. If you leave the lid off, the intake will be pulling hot engine bay air in, which you do not want. Leaving the lid on will be best for performance and will be much quieter.
Mk3 |╠╬╝|SGM|203a|Moonroof|17" Paint/Mach Whls|K&N 57S-4000 -snorkel|FFE RMM|Steeda STB, RSB|JBR bushings
Mk1|╠╬╝|Pitch Blk|Prem pkg|Moonroof|SVT Snorkel|SVT Susp|Steeda STS|Z-Eng RMM|Magnaflow exh
Last edited by TboneZX3; 09-11-2012 at 03:27 PM.