How often does one of these require maintenance or replacement? And, is it affected by the type of driving that you do? If I buy a Leon Cupra 290, the mileage will be no more than 6,000 per year and it will be frequently used for short journeys of a bit less than five miles. Is that going to screw things up, as it would a DPF? I tell you, the stuff I've learnt about GDi engines these past two weeks! Thanks.