Hi there are lots of threads on here about the hot start issue.
This is a relay and a resistor thats fitted between the ecu and the temp sensor, basically fooling the ecu into thinking the temps lower than reality.
I have it fitted to mine. It does work, but now if I disconect mine then I get the check engine warning on, and a different fueling map. No idea why.
The relay on Ebay is a non timed relay, a better fix is to replace the non timed relay with a timed one. This only keeps the resistor in circuit for a short period of time.
What it does is bring in the heater plugs everytime, as if your engine was cold.