Here's the thing. Wingreen's voice is not really distorted. It is naturally gravelly. You can make your own voice gravelly when you talk. The TK simulators have to add static and popping. Boba Fett did not have static and popping.
I used the VoiceBooster amplifier. I put the amplifier in one of the pockets with some foam and I run a wire up through the flight suit. I just simulate a gravelly voice. It also gets you into character.
It is true that there is a slight overdriven effect to Fett's voice and some frequency modulation, but I think you will have a hard time replicating that effect.
I don't really like the artificial voice modulators. They never seem to work. I bought one for a Bane mask a while ago and it didn't work as well as me amplifying and disguising my own voice.