Hope this will help:

SAPS
is an acronym for sulfated ash, phosphorus
and sulfur, the three inorganic
additives that provide key performance
properties to a lubricating fluid’s detergency,
wear protection and oxidation
resistance. Total base number (TBN)
and sulfated ash have had a strong
correlation in past oil formulations, so
most of us associate a lubricant’s SAPS
levels with its starting TBN level. The
appropriate level of SAPS for lubricants
has been the subject of debate for the
past few years. Lubrication engineers
attempt to formulate oils that provide a
high level of resistance to acid formation
while limiting one of the main
acid-neutralizing additives in order to
protect exhaust aftertreatment devices.
So, what exactly does SAPS do?
First, let’s understand the “SA” in SAPS.
Sulfated ash is a term used for materials
added to lubricants to soak up
excess oxidation byproducts and acids
created by exhaust gases. Sulfated ash
is an important component of diesel oil
to ensure long oil life and good engine
protection over time. As noted, some
oil specifications restrict the sulfated
ash content in order to protect certain
emissions aftertreatment devices.
The diesel particulate filter (DPF) is a
good example of an emissions system
device and is a relatively new development
in the diesel world. The DPF is a
large, honeycomb-type filter designed
to capture and burn soot in diesel applications.
It filters particulate matter
from the exhaust so we don’t have to
breathe in harmful material from buses,
trucks and other diesel applications.
As the DPF fills with contaminants,
pressure builds within the exhaust
system. When the pressure reaches a
certain level it triggers a DPF regeneration
process where soot particles
are burned. Materials that don’t burn,
like sulfated ash, build up in the filter
over time and block the flow of exhaust
through the filter. When ash build-up
becomes excessive, it must be professionally
cleaned. The latest diesel oil
specification for 2007 and newer diesel
vehicles, API CJ-4, limits the level of
sulfated ash for this reason. It is normal
and accepted that these filters need to
be cleaned, but the new CJ-4 specification
limits sulfated ash levels to
prolong time between cleanings.
Many European vehicles come
equipped with smaller DPFs that do
the same job as their large diesel
counterparts, which is why the VW
504.00/507.00 engine oil specification
limits an oil’s sulfated ash content.
AMSOIL European Car Formula 5W-30
Synthetic Motor Oil (AEL) has a lower
TBN than many other AMSOIL products
in order to meet the VW 504.00/507.00
SAPS restrictions. VW specifies precise
SAPS limits, which limits the level of
resulting oil TBN.
Now for the “P” portion of SAPS.
Phosphorus is a component of what is
commonly recognized as an anti-wear
agent and oxidation inhibitor, zinc dialkyldithiophosphate
(ZDDP). ZDDP is
very prevalent in the lubrication industry
due to its excellent anti-wear and
antioxidant properties. Alternatively,
larger quantities of volatile phosphorus
contained in ZDDP have been linked
to premature poisoning of the catalyst
surface of three-way catalytic converters
and is a primary reason phosphorus
has been limited in certain oil
specifications. The VW 504.00/507.00
oil specification limits phosphorus content
to help prolong catalytic converter
life. While higher phosphorus levels
can reduce catalytic converter life, a
low-SAPS lubricant is engineered to
provide emissions system compatibility
in both gas- and diesel-fueled vehicles.
The last “S” in SAPS stands for sulfur.
Sulfur compounds are typically associated
with anti-wear and extreme-pressure
protection, but they can also be a
component of corrosion inhibitors, friction
modifiers and antioxidants. Excess
sulfur can contribute to catalyst poisoning
because sulfur is preferentially
absorbed by the catalyst sites. When
sulfur gets into the exhaust stream, it
can poison catalyst surfaces, resulting
in formation of particulate matter. Particulates
in the emissions system can
increase system back-pressure that
negatively affects vehicle performance.
Sulfur is generally being reduced in
diesel fuel and lubricants.
There are a number of very positive
benefits of SAPS in lubricants; however,
as government emissions legislation
imposes stricter emissions limits, the
latest and forthcoming oil specifications
require reduced SAPS levels to
improve the life and performance of
exhaust aftertreatment devices.

So, SAPS actually help to resist corrosion and piston wear... not the other way around...

There is absolutely no problem changing from mineral to semi or to fully synthetic or the other way around.

Yes, lower viscosity oil will warm up faster...

This post has been edited by enhanced vehicle: Jun 9 2013, 10:29 AM

http://www.greencarcongress.com/2011/11/pearl-20111124.html

Shell GTL base oil is categorized under API Group III.

GTL is Group III.

Even if you insists that it falls into API Group V, that does not make fantastically superior than other base oil.

GTL / Fischer–Tropsch is just a cost effective process that can yield higher saturation on base oil, FYI there are other base oil which has higher saturation than Shell GTL base oil.

Please do not think that Group V is better than Group IV and III, Each Group (III, IV and V) has its pros and cons, it all depends what the lubricant engineer is trying to achieve and balance the pros and cons of each Group's base oil with blending of different add pack.

Toyota oil: made by UMW Lubetech in Shah Alam
Honda Oil: made by Eneos Singapore

I think the more relevant website should be: http://lubetech.my/the-company/primary-product-range

They are licensed to manufacture and market lubricant using brand name Pennzoil.

It is difficult to comment the differences of manufacturing, but one has to take note that there is no commitment that the localised production of one specific brand will follow the principle in home country strictly on certain areas, namely, 1) Machinery/equipments used, 2) Blending method and control parameters, 3) Raw materials.