How do I uncensor a censored audio track in a audio editor?

I need to know how to uncensor a censored track in an audio editor. It will be just one step in the larger process of uncensoring a music video by replacing the censored audio in the .vob file with retail CD uncensored track. I can’t replace the whole track outright in some cases. I have to copy and paste in the swear words, etc due to there being sounds, or lengthy audio portions in the video audio not in the CD audio, or the lengths of said audio tracks don’t match. To be able to copy and paste I have to be able make both tracks the same volume (normalize/sound leveling). I have tried some programs that do this. But their results where unsatisfactory. If they are not exactly the same volume wise or damn near to it when you cut and paste, the stuff you paste in will be too loud or soft. So how do I get them this close in volume? Then I need to be able to copy the portion(s) of the uncensored audio over the exact same portion of the censored audio track, no more no less. It has to exact. I have no idea how to do that either. Can anyone help?