i had one, put it in my 32, was no different then the standard one at first, but after a couple of weeks using it i started to notice i had slightly better fuel economy and no speed limit and rev limit lol.
but as r31nismoid said, they can do more harm then good, because you dont know what it was originally tuned for.
mines been running in my car now for over 1yr, only cause i havnt gotten around to takeing it out lol.