No idea it's why I posted it up as it could potentially be quite useful to me.
I change the oil in my 306 (when it's on the road) ever 6k miles as per Peugeots instructions and the used oil that comes out of the sump is BLACK.... Not dark but black probably due to running rich and if you look at the description of that filter it says that it can filter out particulates smaller than .1 micron
I'm sure they are very good but they're rather pricy.
Diesel oil is always black about 5 minutes after it's put in from the soots in the diesel itself.
Also over the years gunge accumulates on the bottom of the sump pan. It's a relatively easy job though to remove the sump pan, clean it out and put it back. A decent garage wouldn't charge much more during a service to do this.
A secondary filtration circuit can only be a good thing and AMSOIL has some very good offerings.
It's something I'd consider as I keep my cars for ages and ages but the problem is fitting the thing - I am no DIYer whatsoever - so I have to rely upon scheduled oil and filter changes.
Diesel engines will always black the oil within a few hours of a change - hence the need for high detergency oils in diesel engines. The oil also needs to suspend the soot particles without having the oil's lubricating and cooling qualities being diminished. Hence my preference for full synthetic oils in ANY car.
I found Amsoil's DEO 5w/40 diesel specific oil to be superb. Pricey, yes, but engines are much more so.
I can't help thinking save your money and do regular oil changes. I mean look at the other thread on here about cars with stellar mileages. That passat didn't have an expensive filtration system, just 68 oil changes.