I removed mine today, washed it in Nitromoors and thinners, left it to dry on the radiator, painted it silver, changed the plugs the leads and the coilpack and it took just over an hour. Its dead straight forward mate.
2 minute job.
Just don't drop your coil pack down the back of the engine, on to your hot manifold.
...so I've been told. Ahem. Carry on!
and for what reason are you even removing the coilpack, no need, to remove the plenum