The diffs in the 4.6 are not the same as those in the 3.0. The 4.6 diffs are quite a bit more beefy. PLUS the carrier needs to be replaced for limited slip.

I'm working on installing the headers and exhaust system from G-Power. Unfortunately the kit isn't 100% complete (and for good reason). The pipes between the collectors and the first resonator are a DIY item (super high volume CATs provided though). As soon as I can find a custom shop with a hydraulic bending mandrel that can handle Stainless (and of coruse, is competent to do this job... looking for input here guys!), I should have the project completed. The headers themselves are a physical direct replacement for what came from the factory (although much higher performance and sexy sounding).

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2008 BMW 335I Blue Convert - still in break-in!
2003 BMW Silver M5 W/ 4.11 gears, Cust Exhaust, Software.
2002 BMW Silver X5 4.6i W/ G-Power Custom headers and SS exhaust, Dinan Throtte Body, S3 Software, Super Charger, 4.11 KMS Posi gears, Custom intercooler, Turbo controller.
2000 Yamaha White Road Star Anniversary Full Dress #322
1999 BMW 528i
1990 Mercedes 300E
1989 BMW 325i
1978 Kawasaki 650 Street Racer