Hello Peugeot experts, yesterday I wanted to plant a set of new spark plugs in my 407 (2 liters of 16V petrol, year 2005). After I had removed the plastic cover from the cylinder head, however, all kinds of components came to light, of which I do not know if one should really unscrew them. Can one of you tell me in short words what to do? Thank you in advance! Best regards, Olaf Schütz