Performance enhancers

Has anyone any experience of the so called performance boost mods posted on e-bay
Have seen 2 types, one related to inlet temperature sensing and a resistor mod the other requiring a spanner and ?
Do they work? is it really that easy and what do you do?
Keith

HI Keith

I saw these ads too,I haven't got a clue how it's done but the one with the Temp sensing and Resistor Mod is obviously telling ecu that the engine is still cold thus keeping fuel mixture rich, would definitely increase fuel consumption and i imagine would affect emissions at MOT time so I would not go for that one. The other I have seen says need a spanner and 1 other tool but won't say what the tool is as it will give away what adjustment is. Also says he has done this adjustment to his gleaming S70 of which he shows a photo, he sounds genuine but I do not like the idea of giving him a tenner just to satisfy my curiosity. I have asked this question on this forum myself in past and got only one reply that he may be making hole in air inlet but I don't think so somehow.If you or anyone tries this could you let us know the outcome.
Cheers