Ignition amplifier on pre-facelift 2.8L

[A8D2driver]

Hi. Can you tell me where the ignition amplifier can be found on a pre-facelift 2.8 A8. The car has started to tick over abnormally (lumpy rather than surging) and with a misfire detectable when driving at 1000 rpm, particularly up slight inclines (under load). The misfire is not detectable at higher speeds. Also time to start the engine when turning over with the starter motor is now slightly prolonged, although the engine always does start. New spark plugs haven't helped. I would suspect the amplifier rather than the coil pack just from general reliability issues reported on VAG ignition systems using this set up. Thanks for any info on this