I wonder how long will the promotion last until, might as well just price is at RM35 as the retail price.

So far not much different in terms of feel but at least I can have a peace of mind that the intake valves, combustion chamber and all will be cleaner with this concentrate.
Yes, from the directions on the bottle, pour it to an almost empty tank and then fuel up. 1 bottle is good for treating 45L of fuel if I remember correctly.

Doesn't matter, RON (octane number) does not influence the cleaning capabilities. Just stick back with your usual brand of fuel will be good enough.
Most but not all, I remember STP recommending to pour it to a half tank of petrol instead. Not sure what's the logic though since either way, we will still be fueling it up to a full tank right away.