Jag V8 Supercharged - Coils & Plugs

[S1M VP]

How easy is it to access and change coils and plugs on a 2002 S Type R?

Symptoms:
The engine mgt light is now permanently on, restricted performance on and doesn't seem to be firing right at all especially at idle, but seems to run ok once going but is constantly to restricted mode.

Thinking if they are a relatively cheapish/DIY job it's as easy to change them and see if it is that, otherwise take it in to be looked at by dealer.

[stevieturbo]

Any half decent mechanic should be able top perform a diagnosis on the car, rather than swapping parts at total random.