Having read the first post again, and the next 30-odd pages as well, this seems to be the story -
The standard front PCV check valve can allow some boost from the intake manifold to bleed back into the engine crankcase causing poorer mileage, a rougher idle, and oil being blown out of the oil cap. This is made worse with higher boost levels from a remap. The kit eliminates the front PCV that goes to the intake manifold and instead routes everything through the rear PCV which goes to the intake pipe between the air filter and the turbo compressor wheel (possibly after the MAF but not sure).
To answer my previous question the oil fumes still enter the combustion chamber as usual, just by a different, longer route through the turbo compressor, then intercooler, then the intake manifold. So a catch can system is still required if you want to stop that happening.
The guy at BSH who makes these calls this a Stage 1, and adding a catch can system as Stage 2 -
"The Stage 1 setup deals with the performance issues that are caused by a loss of boost.
The stage 2 takes this a step further by accumulating all of the oil that is passed through naturally by the PCV.
Oil is bad for the internals of the motor and bad for performance as it lowers the flash point of the gasoline being sprayed in (makes it more likely to detonate early)."
Also - "Stage 1 addresses the issue of people who chip their car and push 20+ psi of boost and blow that flimsy little plastic check valve in the PCV."
Sounds like this PCV revamp kit would be a good idea for anyone running Revo Stage 2+ or Shark 3 which are around 20psi.
Interesting comments on maintenance -
"The piece is likely just going to have some oil residue on the back of it after some prolonged used. The OEM gasket will keep it all self contained, though, so it won't be blowing oil vapor all over the engine like people were experiencing with early stock PCV setups.
Just remove it and clean it off with some sort of lint-free rag or towel (so no fibers are introduced into the engine when you reinstall it) and then screw it back into place.
Q. How often would we have to clean the stage 1 set up ?
A. If your good about changing your oil then likely never, but if you go to long without a change then a quick once over to make sure there is no buildup isn't a bad idea."