You really don't need it if you don't mind a very slow servo and a RX that may not function very well.

A booster raises the voltage of the 1S battery's 3.7 volts to that of 5 to 6 volts. A receiver pack delivers the same voltage but doesn't get it from the main pack (it is a battery either a 4 or 5 cell NiMH or a 2S LiFe or a 2S Lipo with regulator to bring down the voltage to 6V).

Both plug into the receiver's battery slot.

I've used both and haven't had a problem with either. The Novak booster has a LVC to prevent over discharging the main pack. I switched over to using a 2S 220mah LiFe (6.6V) but you need to charge these with a LiFe compatible charger (I have a couple).

Can I feel any difference? No. The LiFe pack allowed me to get rid of the weight I used to balance the chassis.