Worth the extra premium/weight and less mpg over a 2wd Sport ?

They're alot of money for a small car, BMW E39 530d and E46 330d money.

What to look for, general advice and must do mods?

Would a Stage 1 re-map make the clutch poo itself as there seems to be better gains to be had over the 8P 140 & 170 ?

Has it a dual mass flywheel ? I have no experience of them and have heard of single mass conversions.

What clutch and or conversion for @ Stage 1 for a near stock feel ?