I mostly build OOB. As a matter of fact the F-4B that I am building for the contest is my first venture into aftermarket add-ons other than decals. I did do a slight mod on a Tamiya F4F-4 to correct the floor and add the appearance of a fuel tank under the cockpit but other than that I'm OOB. A big reason why I build OOB is that years ago B.K. (Before Kids ) I started getting into contest builds. I started getting so anal about details and paint schemes that I never finished anything. I wanted perfection and nothing else was acceptable to me. Sometimes that old demon still raises his head and I have to beat him into submission but in return I get joy out of my builds not stress. ;D