I recently bought an XKR, and I am getting an unusual fluttering noise under whenever I accelerate. sounds like (frfrfrfr..). Between this and the supercharger sound, the car sounds like a washing machine on high-spin! local Jag dealer says it's normal.. I owned a straight six X300 XJR before, and I enjoyed the engine sound on it. I'm considering a sports exhaust and free-flow induction kit to recover some V8 sound and drown off the other bits. Any advice?