Hi,
So, do you have the mod, and just want the right sound for it?
Or you don't have any such mod, and you just want the sound from it?
And yes, Content Manager makes it super easy to swap sounds (but backup the one you're overwriting first because you can't get it back without downloading the mod again). Go to the Content tab, select the car to receive the sound, and the option to replace its sound will be at the bottom of the page (assuming you also have the car you want to take the sound from). Should be self-explanatory from there.