Since I could not find any good sound mods for the tank I decided to create this
It's captain falcon's sounds for the tank, I'll upload it to l4d2maps once I make a video
You can download it here
http://www.mediafire.com/?oqai64syckbq0qoHow to install, well just extract it here
C:\Program Files (x86)\Steam\steamapps\common\left 4 dead 2\left4dead2\addons
If you got any problems installing it just hit me on steam, enjoy!