i've been wondering about this dilema myself.
My view is that the only way it can be done is to make a "tray" to house a flat filter that will go between/under the hat and on top of the blower. If fuel is going to be injected into the blower, then the tray must go under the hat but before/above the fuel block.
a) If the filter does cause a restriction (would it really be that high a restriction.....?) then can't we comphensate for that by adding a little more boost? i'd be willing to sacrifice a little power for protection. Has anyone actually shown how much (if any) restriction an inside filter really poses?
2) As far as the streetcatcher thing; My feelings on these products can be summed up in a not so nice word that begins with a "W" and ends with ing. If you're going to do something, then do it the right way. On the other hand, if it's looks you're after then i suppose they're ok. i'm actually suprised D.G. would have these things on his website.