Bit of a daft question...

ahhhhhh what kinda petrol engine s3 s4 rs4 etc etc

stronger how??
depends on the components of the engine. but obvously diesels have a lot higher compressions and forces on internal components. so it cant really be compared. but then, take a diesel rod thats used to x amount of forces, and a petrol which will be made for less, rod for rod the diesel will likely be made to take higher stresses, and stronger.

but if your talking about revving both engines to the same revs, the forces acting on the diesel will be greater, but the components will be stronger. and the petrol engine will be made to do the same all day long. so theres no reason why they wont last exactly the same time. bit of a silly question, or rather an inconclusive one

standard engine vs standard engine, they are made to do what they do, and both engines should take the forces they do, so there is no reason they wont last the same. but compare individual components, the diesels require to be stronger.

speed is irrelevent, the engines are turning the same speed, the diesels engine will be under more loads inside, ie compression, tension, torques. but its made to take those stresses. unless there is an unintended weak point, both engines will run at that rpm for a very long time. its how they test the engines. and most will have to reach a benchmark miles, or hours, set by the manufacturer for them to be mass produced, likely the same benchmark if its the same manufacturer.

ahhh i see now, sorry dude

diesels dont rev as high as petrols cus they physically cant.
the components in a diesel engine have to be stronger (and so heavier) due to the way the engine burns the diesel with a higher cr (20:1) in an explosion rather than a rapid burning (10:1 petrol).
the weight of the componets means they cant reciprocate as fast as the lighter components in a petrol engine.

this has no effect of the longevity of the engine as both are built for purpose.
but, if you fitted, say standard petrol engine rods in a diesel engine i bet they'd turn banana in a short length of time!