Someone I did know tried that and he blew up two oil coolers. So I thought that the oil pressure is to high if you connect the oil cooler this way.
But probably they were not the correct oil coolers or wrong modell.
As said, though, the standard oil cooler isn't a bad setup so why change it?
No it isn't, why would you want the oil temperature over more then 100 °C the optimal oil temperature is 80 °C
This setup is only for the eco shit emission, if the oil is quicker warm the engine emission are better.
If you always drive the speed limit never drive sportive, do not tow a caravan etc. then it will work, but if drive more sportive and faster (in Germany) then the oil cooler setup could be better.
I'm not sure why you have experienced coolers bursting. The oil pressure is limited at the pump by a relief valve so no point in the system downstream should be seeing excessive pressure, although after a cold start it will be highest due to higher viscosity of the oil. I have never measured it on an Omega but I wouldn't expect to see more than 5 or 6 BAR even when cold.
Oil temperature needs to rise above 100 C from time to time to drive off any water vapour from combustion products. You see this in cars only driven locally as mayonnaise in the oil filler. Modern oils are generally fine up to 120 / 130 degrees C. I'm not sure where the "ideal" of 80 C comes from, but the main thing is that the oil has the right viscosity at the temperature at which it runs, which, for synthetic oils covers a wide temperature range.
With a large oil cooler with decent coolant flow around it, there is no chance of the oil temperature rising significantly above the coolant temperature regardless of how hard you drive the car, and there is also no risk of overcooling the oil during urban driving either, which is often a problem with external oil coolers.
You also have the advantage of no flexible hoses in the oil system, so much reduced risk of a hose rupturing and losing your oil pressure.
The final point I'd make is that sometimes it's not a bad idea to modify a car, but, there's no point in doing it "blind". Measure first how the oil temperature behaves during different driving conditions and then decide if you need to make a change.