| I've seen knowledgeable people argue equally strongly for undertank and for in-tube air filters.
I think what it all boils down to is this:
1. Undertank, better filtration and protection for the motor if the tank comes off. More difficult to install on shower type injectors.
2. In air-tube, better performance. Mucho cheaper.
Bearing in mind that Ducati have a performance oriented philosophy for every part of their sports bikes (visible or not), I tend to think that they put their filters in the air-tubes for a good (performance) reason.
Spinoli | 
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