Read some discussion of extra fine oil filtration on the Audi list, using
Amsoil stuff.  Checked their website and phoned local rep. for glossies/costs.

  FYI  they sell a dual remote oil filter system for about $250CAN, consists
of firewall mounting plate, a 3-5 micron bypass filter that passes/cleans
all the oil in about 5-10 minutes with a regular filter for normal
filtration, plus and adapter plate and hoses which replace your existing
engine filter. Kit comes with 3 adapters, will post when more info arrives.
The bypass filter will pull water out of the oil, holds up to a pint or so.
Why you ask???  

The claim is 25K miles between filter changes, and ...  100K miles between
oil changes.  Replacing both filters requires about 1.5 quart top up which
'replenishes' the additives.  Naturally they rec. their synthetic oils, 0W30
or 20W50.  The system adds about this much capacity to your oil, better
cooling I'd guess.  Could likely sneak an air/oil cooler into the hoses if
really wanted. The do rec. regular oil analysis for particles etc. In the
long run this could save a bundle in oil, provided it didn't just leak out
onto the drive anyhow.  Buying 2 quarts of oil every 2 years sounds great to
me (barring normal consumption), as does changing the oil once in a
lifetime.  They also sell synth. gear oil, 75W90, and 85W140.  I don't own
shares etc.!!!  Anyone used Amsoil have any opinions on this concept?
Thanks.  Tim