I had a similar gadget that i got off Ebay and put on a Z1000. The one i bought only cost about $20 though.Definately gave it more berries in the low to mid range (alot easier to stand it up). Top end? unsure. All they do is trick the airbox sensor to run super rich. Have a look at how the bike is burning. Mine used to run very sooty and black at the pipe. Running the Zed to redline and backing off sharply made the bike blow large 1 ft long blue flames out the pipe

as it backfired all the way down the rev range
In the end, I took it off as i was concerned about the long term effects.
The problem with running these cheap alternatives is you dont know if its leaning out at certain points of the rev range. After trying one out, id buy a PC instead. worth the coin