>>But, wouldn't the "car" also be a component, comprising subcomponents? So, in that case it would involve pieces from all the layers.
>
>But wouldn't the car be the application? Stictly speaking the componets are COM servers and can't have a UI so you can't group them together. Correct? I'm just guessing at this point so....


No, COM servers can have UI. VFP DLL COM Servers don't support UI, but an EXE can have UI. You can call Excel, Word, Visio, and others as COM servers and all can have a UI.