Why do you want to remove springs? To lower/level? There are better ways to do it, if you choose to level the rear to match the front. I have heard guys complaining that when removing springs, the ride gets really squishy, same is said about aftermarket lowering springs and some sring under axle kits. You don't want to loose the handling and control, so I'd keep the springs where they are and how they are. There are several companies that make adjustable setting lowering shackles that work with the titan, I used some cheaper amazon ones, which lower too much and cause contact with the underside of the bed, and I have PRG adjustable setting drop shackles. The PRG's are heavily built, much stouter than OEM and leveled my '14 4x4 almost perfect...within ~.5" front and rear depending how much fuel is in the tank. I recall from previous reads that the bottom overload spring should get you about 1-2 inches of drop if you take it out. Again, I wouldn't, and nissan recommends the OEM u-bolts are used only once, and should be replaced when removed. The u-bolts are expensive and imo probably don't need to be replaced when removed.