The 2004 BMW Z4 2.5i is a moderately difficult car to maintain, but should be relatively straightforward to repair for the experienced car owner. Changing the engine air filter with reliabliity is easy, as you only have to disengage a few fasteners in order to lift the housing for access to the filter. The tail light is easy to access, as there is a designated panel in the rear of the vehicle for access to the bulb. Other models make this access more difficult. Checking the oil level is easy to do, as the oil dipstick is easily accessible in the engine bay.
As said earlier, there are some tough repairs on the 2004 BMW Z4 2.5i. In order to access the headlight, you will have to reach through the wheel well lining. This can be tough, as the lining can grow rigid and tight to the vehicle over time, making it hard to pull back. To access the petcock, you will have to remove a large panel from beneath the vehicle first. This will require the use of a few tools, and for you to crawl under the vehicle in order to complete. You will need a few tools, and have to remove a few panels, in order to access the cabin air filter. Other models make this access less problematic.
Hans Angermeier has produced over 100,000 videos showing drivers how to fix things on their cars. He has broad expertise on basic repair procedures covering the majority of cars on the road.