do these things actually work?

[smogga]

https://cgi.ebay.co.uk/MOD-CHIP-20BHP-RE ... dZViewItem

[Bumpy macaroon]

'REMEMBER I AM A TRAINED MECHANIC'

I would stay well clear, its a resistor you bolt on somewhere which tells your car it is colder, your ECU then increases the fuel mixture and burns more fuel . Its not a remap or anything really clever such as starchips etc will provide which changes the fueling and improves mpg

also anyone that has to mention that he is a trained mechanic probably isn't, 'yeah mate i'm a black belt in ju jitslapheed doh and well hard'

[Mattj]

id personally stay well clear and try and save up for a dummy ecu - only because it will inject more fuel - so your mpg will go down and also in the long run personally would damage the engine - get a superchip or dragon box as they are specially designed for the megane and alot of peopl on here have used them and speak highly of them