Depends on what the question is.
Since we don't *yet* have a dedicated 400i subforum... <ahem...> I recommend asking the questions you might have in the most topic-appropriate forum. For example, if it's a maintenance issue, I'd ask in the "Technical/How-to" forum. If you're showing off photos, ask in the "Eye Candy" forum. And so on.
Speaking as a 400i owner, glad to see you here!