ok so i just bought an 18" fi btl fully loaded dual 1ohm....i originally wanted my box to be 40"x30"x20" with a port size of 10"x18" (which would pretty much take up my whole trunk space) tuned to 35hz ....but ppl tell me thats probably too big...its goin in a lincoln navigator...can anybody PLEASE just tell me if thats ok or too big or what it is that i have to fix to make my sub hit HARD! also how should i face my sub and port? i originally thought both up, but i heard sub facing up and port facing the rear is better, is this true? ok well first off i working with a hifonics 2000 watt brutus for now...hopefully a saz3000d soon...i listen to mostly rap but pretty much everything with bass...im trying to get that deep low bass thats gonna vibrate the entire block!! SOMEBODY PLEASE HELP!!!!!!!!!!!!!!! thanks!!