you need to remember how much oil capacity our cars have.
the "3000" standard is for cars with 5 liter capacity and pathetic little oil filters.
my car at least has 8 liter capacity and a massive filter, and BMW's recommended service interval on dino oil is 15000 miles!!!!!
of course thats rediculous, 7500 should have been the number for dino, with 10-20000 for synthetic depending on oil TBN and driving style.
for you cars with smaller spin on filters or small sump capacity, take 25% off of that, so max 5500 for dino, or 7500-15000 for synthetic.
the larger synthetic interval number is for those who can change the filter half way without losing much oil, or those who have a bypass filtration system.
Alusil, Dinan DME | ITG Air Filter | Eibach/Bilstein HD | 26/20 Swaybars | Iridium plugs | Depo/ProLumen HID | Optima batt. | no AC | Stoptech brake lines, Frozen rotors, brass bushings, Superblue