Autosol chrome cleaner and very fine wire wool.... Rub the autosol into the wire wool until its all soggy with it and then start giving the chrome runners a good going over.
Leave it for a few minutes then rub then down with a clean soft cloth.
Use Mr muscle oven cleaner spray on the rest of the block. plenum and alloy covers. Again leave it for a good ten minutes and if you have a steam shark or similar hand held steam cleaner in the house use that to steam it off it's totally safe and can be used on sensor plugs etc as there is no water pressure, it virtually evaporates along with the dirt.
Dont bother trying to polish the alloy, it goes mottled and horrible.
Instead if it's really bad, sand down with 800 then 1200 grit then clean off with brake cleaner and allow to dry.
Now use a spray paint can (mercedes bright silver or honda saturn silver) is the closest match...
You don't need heat resistant stuff, it doesn't get hot enough to peel ... Follow with a good few coats of laquer...
Now here is the best bit... The Alfa Romeo and V6 24V lettering? If you don't have any caliper paint and a fine brush, use your missus's blood red nail varnish
... Again, it wont get hot enough to peel and once you give it a couple more coats of laquer, its tough
Baby wipes for the balck plastic and silicon lubricant sprayed onto a clean cloth for the rubber so you feed it and prevents cracks etc...
The steam shark doesn't half get into the nooks and cranny's and makes short work of the filler caps that get stained with mucky, oily fingers