Spark plug service for the AJv8 is every few years the exact time escapes me, my 3.0 S type specifies 100k service interval for the Plugs so thats probably the same for the AJV8.
They have Timing Chains, very beefy compaired to the M62
Oh and it's coil on plug ignition no dizzys or rotor arms
The ignition system is reliable, just watch out for the odd coil as they can fault
The AJ41 is a Bored/Stroked version of the 4.2 which in turn is stroked version of the 4.0 which was a bored and stroked version of the 3.2! got that? good.
it is very robust in its design and is well proven
They also have VVT which is lightyears ahead of Vanos in it's durability!!
.
With versions of this engine putting out 600hp at santa pod with a twin scroll charger and NOS
Did i say they're good motors?
The S/C has forged internals which is good for POWAH!!
But the Cast internals of the N/A are plenty beefy
On a slightly separate note.
Check for corrosion around the rear seatbelt mounting area and rear subframe the L322's are getting to an age and the tin worn has managed to sink it's teeth!!!
They rust!!
Check 'em properly alot can hind under a shiny exterior