I was told that there is another product that supercedes Sprint Booster.
Its called (get ready for this highly creative name) Power Pedal from a company called Tunekit in Germany.
Plus is that its from a German company which probably means its got to be TUV tested and gives me added confidence that it does what it claims.
The difference with this I am told is that this is variable/adjustable sensitivity vs dead settings for sprint booster.
No affiliation with them whatsoever. There seems to be a US distributor as well so good luck.
TuneKit - power of performance