Yes I see what you mean, that sound is just right. What brand X-pipe did you buy and what diameter is the piping for the X5? The guy in the video went with Magnaflow, they show three different pipe sizes.

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2002 X5 4.6is
1999 C5 Corvette
1992 Mitsubishi 3000GT VR-4
1994 Kawasaki ZX-9R
2005 Mazda 6 Wagon (Wife's)
1991 Mitsubishi 3000GT VR-4