in comparing my e46 M3 to the E53 X5, IMHO the inspection 2 price and/or extended maintenance -

M3 - worth it
X5 - not worth it

clutch coverage and valve adjustment were 100% worth it for the M3

X5 - parts you can get for cheaper and the majority of the inspection are checks.

A great inde will be your best friend for inspections on the X5.