into the confines of the underhood and around carb. Obviously you want to minimize sharp edges/steps and lean toward base-ball and larger curves. Get a look at the used NASCAR air filter housings on ebay for how to do it right. They even use fins in the middle of passages to stabilize the flow. Any filter will have restriction and alter the stability of the airstream, just that a large filter will have less effect on flow. The more media the lower the velocity through any given area of that filter. The lower the velocity the better the filters ability to capture and hold contamination as well as the longer it will go w/o increase in delta-P.
