I would like to inquire if any Audi drivers in this forum have
installed magnets on their fuel line intake.

It is an old idea that comes from the second world war when the Brits
were putting those on their Hurricanes and Spitfires to boost them up
against the german warplanes. The RAF also indicated that they were
also acheiving fuel economy. Even the USAF did install them on their
Mustang. The germans were putting magnetic rods inside the fuel intake
and this would reduce the amount of black fumes coming out of their
engine exhausts making them less likely to be seen.

There are lots of websites selling them in the UK or Germany,

Even Jacques Calvet (former Peugeot-Citroen president) has once said
that motors will be improved with proper use of magnetic technology.

In some other car forums there is much controversy about these since I
have seen writers insulting others abou this issue which I believe is
worth gathering facts from the largest amount of trials.

My own experience now is that I have installed two magnets from
Magnofuel in Germany on the plastic tube before the fuel pump and my
car which is an Audi 80 with a 1.9 L TDi engine has seen dramatic
acceleration improvements in the low revs. This is important for this
car since it was lacking punch and now it is quite decent in ciry
traffic.

LHR