I'm not sure because I have a different model, but I was having a similar problem with a sound coming from the rear of the car over select pavement separations and the like. It ended up being a loose exhaust hanger and the muffler or pipe was hitting the car's underside. I'd say check all your clamps and hangers on the exhaust. Hope this helps.
Proud Owner of a Legend Lime 05 GT
- Black Leather, 5 speed, IUP
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