I had catback and sports cat on for a week before putting the manifold on which sounded awesome. When I put the manifold on there was no change to the sound just pure raw power
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Colorado Red 07 Plate ST

Mountune CAIS - 60mm Throttle Body - Full Resonated Milltek System - Bilstein B12's - 300mm front discs - Gloss Black Team Dynamics Pro Race 3's - Tints - Red-Black DMB Badges and loads of eBay stuff...