As far as whether you really need one, I'd say don't wast your money for the level of bracket of racing your doing. Guys that do run them are heavy bracket racers that race allot of back to back rounds and will run in two different brackets on the same day. The greater percentage of bracket races don't use one. Only reason I have one is because my pan had the provisions for one, and the kids bought it for me as a christmas present.
The things they hide, the way they spin things, the excuses that they make and the things they omit.