I think they used Syntium 800 10w-30 which only come in 3L bottle instead of 10w-40 (4L)

No la.
In manual stated use grade 10w-30 or higher.
That y they give u 3+1.

Chasis: 6XX.
Received: 27/04/2012.
Problem: Wind noise C pillar passenger left - just tighten the rubber (outside) around C pillar - problem solved.
Always thinking positive with my car.

It's enough people have been play & laugh with a photo of the broken drive shaft of test drive car previously.
Either safehouse word true or not, let him with his car. Thinking positively. Drive carefull with our car. If he post the photo here, it could be a bullet for proton basher either here or others forum.