Well first of all, you should never take of a tyre that is on a rim and try and reuse it with a another tyre on the same rim.
If you are wanting to race Take Off's or Sorex's. There are the best tyres used for racing. With Take Off's you are supplied with the inserts and with Sorex tyres you arn't. You'll have to buy them seperately.
But this way you can choose you inserts depending on what you want the tyres to do!
Have a think about it.