i dont know about the extension question, however here is a picture of where the filter actually goes (without the bumper on)...its tucked into the front of the bumper and surrounded on all six sides by walls...inside the red circle is where the filter actually is once installed, but once you put the bumper back on (or close up the fender wells depending on how you accomplish the install), it will be covered up...we have absolutely no drainage in lawton, ok and when it rains it gets deep as hell...we just had a rainstorm and i drove right through all the deep puddles with no problem...if you want to waste your money on the bypass valve, thats up to you but i dont think its necessary.