I disconnected the last 2 pieces of intake on my 90 b12 but didn't notice much difference in power or sound. While fooling around some more I noticed that there is another piece of of the intake screwed onto the inside of the blue cover. I removed that and took away the rest of the intake leaving me with just the blue cover and stock filter. I noticed more power in the higher rpm's and my car has a deeper tone to it now. I am trying to find a good K&N filter to fit the car well as they don't make one for the 90 sentra. You might wanna try removing all of the intake instead of just the last bit like you have done sentrastud and see how much of a difference it makes.