Need a new M5 to replace E60

[Carpmart]

chaps... Need some advice pleas!

What makes the most sense? A new M5 or a 2-3 year old car?

What sort of discount from list and or finance deal should I be able to achieve?

Worth trading in the old M5, or sell privately?

Would agreeing a deal in the next two days help me get a very competitive end of quarter offer, or doesn't it work like that?

Thanks in advance for the advice..