When I put my 8 in park or netural, and rev the engine to around 2k - 3k rpm, I hear a sound like water gushing through a pipe going through my exhaust. The sound only lasts for maybe 2 seconds. This happens after engine reachs operating temp, and after running for several miles. Is this a normal sound that all AT owners hear or is this something I should worry about.

http://www.rx8club.com/showthread.php?t=20371&highlight=water+dash

Thanks. I did a search but I guess I didn't use the right words. Thanks for the quick response.