Anyone try the CFM+ intake manifold? http://www.cfmplus.com/cfmplus_59prod_09.html

if we where talking about high pressures then yes I would worry about that. A guy in the department I work is going to bring in his stock air horn so I can see how I can remove without having an issue. The only thing it needs to support is it's own weight right? Maybe weld in a boss on the outside to extend the bolt, say .500"? After I can lay hands on one I can get an idea as to how much marital can be removed.Don

Ummm... Could you possibly use a 24V air horn instead without the choke point. They look almost identical.

Yes, that is a common cheap mod.