I recently had the X-pipe installed on my 4.8is and holy shit is it awesome. One of the best mods for this car by far in my opinion. The startup sounds is amazing. The x gives it a really deeper throatier v-8 sound. I will post a sound clip and provide link

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2006 E46 M3 ZCP
2005 E53 4.8is
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2017 F80 M3/ZCP (SOLD)
2000 E39 M5 (SOLD)
2011 E92 M3 (SOLD)
2006 E90 330i (SOLD)
2009 E92 335i (SOLD)
2011 Range Rover Sport (SOLD)
2011 Infiniti G37S (SOLD)
2008 Acura TL Type-S (SOLD)
2008 Infiniti G37S (SOLD)
2006 E90 328I