Took my 2008 F430 in for the annual and mechanic noted a very light leak on each rear left of both valve covers. I let it go because I can drive 100 miles and I'll see maybe a drop or two. The Mechanic told me the repair was an all day job which in this area is around $220-240 US an hour at most of the shops. It does look like a lot of labor. I note there are additives that can stop leaks like Bar's Leak Seal Repair but is that advisable?