Hi guys!
Greetings from Russia. I was serfing net, trying to find out how to make my 2,2 z4 a little faster, when i found this thread.
I am pretty impressed that Xado is known worldwide. But here it's not very popular. Many oil-makers here claim they use some "magic-old-forgotten-soviet-secret" technologies. Xado is just one of them.
As far as i know, original Castrol SLX (main BMW oil supplier) isn't a simple oil too (even keeping in mind sludge problem). There is a good reason to use original oil, especially when you push your car to the limits.
For some reasons, many BMW-fans in Russia use other oil brands, uncluding Xado, but there is a clear leader (!!!not the most popular one - it costs 3 times more than Castrol, but the most respected!!!): Motul 300V.
There are many different oil additives on the market here (Xado was one of them in the begining). Every makers claims they have "oldsoviet/revitalisation/remetalisation" effect. But the truth is - they are useless (at least not harmful for your engines). Of course they do smth. But it's definitly not a secret technology and for some reasons Castrol/BP/Mobil ect don't add them during the production.
PS
I'm writing it, 'cause I saw a working additive. Spoke with it's inventor. It's developped for army in "74, to compensate the lack of good oil and gas during war. It makes a terrible oil acceptable for engines. It's not a simple fill-n-go procedure: First additive prepares the engine, 1000-2000 km required, then you have to change oil and add the second one. The newer the engine is - the better effect. Adding from 7 to 15 % of output with a good oil. But it's not for sale yet. Mb in 2011.
PSS
Pls, keep in mind that my russian is definitly better than english. =)