Probably a load of crap. Your motor wouldnt even know what to do with that much air in its stock form. You need to upgrade the cam shafts to make real use of all of that air.
Breather mods help the car breather, and free up some horsepower choked out by the restrictive system. You dont actually MAKE power until you upgrade the internals. (camshafts, pistons, bore)
Hmmm... I heard It's difficult to break 300 hp with a Honda.. I dunno that's just what I heard.. I dunno what a respectable amount would be for an integra.. I'd love to run 12's or under someday:twisted:
300 all motor is pretty hard. 275whp can be done with a b20 vtec and skunk2 pro2 cams. toda vtec killer cams and high compression pistons with ITBs may get it for ya...but you arent going to drive it every day or ever i guarantee you