Hy chebbydog, all the hydrovac brakes I've driven have been very easy to stop, anything more than a light to moderate pedal pressure will lock the rear brakes up. A simple test for hydrovac function is, run the engine for a bit, then shut it off and pump the brake pedal a few times, now with your foot pressing down on the brake pedal restart the engine, if the hydrovac is functioning properly the brake pedal should go closer to the floor when the engine starts. As to filtering the air, yes you should do that, the factory had a separate small air filter, but I can't think of any reason why you couldn't plumb it to the air filter, hope that helps.
