The sounds in TSW do need some improvement. I have found a way to add some dynamic range to what is there. For those of you that have Realtek HD Audio you can open up the control panel and in sound effects you can adjust dynamic range in the equalizer settings. There are presets, I am using racing, or use the equalizer sliders to set it for your particular environment. It will give a bit more rumble.
http://s16.postimg.org/qsw54yvt1/screenshot_163.png