If you are thinking of the bus drivers (there are 4) it doesn't enable 16Mhz, just makes it more reliable. 16Mhz mods that switch the CPU are pretty fiddly to get working stable.
I still need to play around more to get it better, but the speed gains are not really that amazing. Faster on some stuff but generally not amazing. Crank the bus speed up if you have multisync monitor :)