I replaced pretty much all the hardware and electrics on my Richwood Explorer, but the sound is much better. Part of the problem with cheap bridges is the saddles are rubbish so that the strings don't transmit any vibration into the wood.
Many copies have Gotoh machines on them, it is worth checking to see if this is your case, as if it is, I would not replace them. If you have some other fake Grover/Schallers, then get Gotoh's as they are the best for the price.