Remembering why I
dislike working on
AO Silver Member
Join Date: Sep 2001
Dave Walker did a test of these things for CCC a while back. His conclusion was that as measured on the rolling road on the day, it made zero difference to the power, economy, drivability etc etc etc. The only thing that was affected was the wallet of the purchaser and the noise levels inside the car.
There is always an element of psycology with these things. We pay good money for them so want it to work.
Until you measure it, you can't prove anything.
Just my 2c