I'll expand on that a bit.
I managed to get the V8 for significantly (4 figure sum that starts with a 3) less than a diesel in comparable condition. There isn't a lot of demand for the V8 petrol because everyone goes 'GOOD LORD THE FUEL BILLS'. This in itself buys a lot of fuel.
Then factor into calculations....
- The diesel really doesn't exactly excel in the economy stakes. Real world calculated figures (not on the dash computer) see the diesel averaging low 20's combined.
- The fact that for the age vehicle I'd be buying the diesel will be getting close to the usual EGR/Injector/Turbo woes
- Diesel costs more than petrol
- The diesel uses a belt that costs a fortune to change and the petrol has a chain drive....
- The diesel seems to have a habit of causing gearbox problems, I couldn't find a single petrol that had this issue.
- The petrol and diesel of this age have the same road tax cost.
- The petrol drives a lot nicer. There isn't a price for this, but the noise, performance and refinement are worth
I did do a proper spreadsheet, but I don't have it to hand. I think you need to cover serious (something close to 50,000) fault free miles in the diesel for it to cost less than the petrol. By which point, you might be needing to change that cam belt again and it all goes to the petrol again.
Sure you can do some mitigation and get the EGR blanked off, but that in itself isn't free and that eats into running costs.
Everyone has a reason for why they will have picked a diesel, and it is probably down to availability of the petrol or a preference of a diesel.
Everyone has their choice, and I have always fancied owning a V8. Sure it isn't in a sport chassis, but I really enjoyed the drive. It had enough go to make the Discovery even feel... brisk .. whereas the diesel just seemed a bit exhausted. I'm told a remap does wonders though.
All of the above is written with a bit of man maths thrown in, but seriously, there wasn't much in it.