Offshoreonly.com - Questions about Gil dry exhaust

I have a project boat that came with Gil dry exhaust. One manifold was leaking out of the casting plugs - I tried to get the plugs welded with no luck, so now I need to either get a new set of Hardin Marine Gil replacements or maybe a completely new wet system from some other manufacturer. My questions. Do I have to worry about water comiing back up the tails from wakes and waves when I'm just floating? The exhaust did come with drew marine shotgun tips. I ask this because the exhaust has no internal flappers. Just wondering if I should go with eddie marine wet exhaust with exhaust tips that have flappers? The cost of a whole eddie marine wet system is less then the cost for the Hardin Marine Gil replacement manifolds without riser/tails. My motor is just a gen 6 454 425hp crate motor.