I've got a set of Index 9 injectors from my 2013 335is, which have 30,000 miles on them. None were giving me any problems, but I found a set of Index 12's for a deal that I couldn't pass up, so there was no reason not to upgrade. I've also got new injector seals (My new set came with 12). For $2 extra per seal I'll include one! Price is $60 each, or $320 for the set, and I'll ship to Murika for free.