Oil Additives - Rislone, Marvel Mystery, TufOil?

[JRheeman@aol.com]

     Recently, I've read or heard about a number of oils/oil addititives/oil
substitutes and I was hoping members of the list could help me out.  
     The last time I had my oil changed, my mechanic suggested I try a
product called "Rislone" to help alleviate the valve ticking in my '90 CQ.
 He said just add a quart when I'm down a quart during the next few oil
intervals.  I tried searching the archives, but no luck.
     In the most recent European Car, I read a short product blurb about
TufOil and how it is claimed to be the most lubricating substance known to
man.
     Finally, there was a recent thread about Marvel Mystery Oil and it
interested me enough to buy some.  However, I am a little hesitant to put it
in.  Thus, I have a few questions:
1.  Do any of you feel strongly about these products?
2.  Is there any long term benefit/harm in using these products?
3.  Are these products similar and is one better than the other?
     I would really appreciate any help on this issue as I want to do the
best thing for my engine.  Thanks in advance.

Jason Rhee
W. Bloomfield, MI
1990 Coupe Quattro