Scania Engines

Hi all,
I think I might have posted on this topic already. Never mind,
I’ve still got the 13 plate R480 (ad blue), which I thought would be good.
What a load of junk! I chopped in a 420 volvo for it, and it doesn’t go one bit quicker than the aforementioned Volvo , and is around half a mile to the gallon worse on fuel. I struggle to average seven mpg. It has what i assume is the standard final drive ratio, and as i do very little motorway mileage, i dont spend much time in top gear. It also seems very low on torque compared to the Volvo Its one and only redeeming feature is that it has been very reliable, but then it only turned 380, 000km last week.
Two questions. Does anyone know if it’s worth trying to get it remapped, and also, is the 490 as much better an engine as some say it is?