I went through all 50 pages of the above linked discussion last night. It was supposed to show evidence that it helps with piston slap (that I have in Toyota's 2GR-FE). Well, no one did mention that. I found some other forums claiming that though, but nothing concrete.
Since I wasted some much time, here is the summary:
Almost all people said that TCW3 made idle smooth and quieter. Some people mentioned increased MPG, but some later retracted that, so it's inconclusive at least. Some people mentioned exhaust louder and more exhaust smell. A few people who checked plugs or pistons agreed about no deposits whatsoever.
So, I decided to try it myself. Unfortunately, my tank was full, so I decided to add TCW3 regardless just before driving thinking that gas slushing will mix it. WRONG! After 1 mile of driving, the engine hesitated some and idle RPM went down below 500 several times, but recovered. I guess too much oil went through. Later, no difference I could feel or hear whatsoever. I will keep using it for a few tanks and report back. The car is rarely driven though.
The only concern I have right now is whether any unburnt TCW3 can wash to engine oil and dilute/contaminate it.