I just installed mine last week as well...
The install was relatively painless. I had a bit of a time getting the wiring harness off the existing intake and getting to the clamp on the rear intake to loosen it.
After everything was loose, I had to work a little to get the current air box out, but patience prevailed and it finally popped out. After that, everything was a piece of cake.
As far as "even pressure" to both filters. I think that is a ridiculous claim (probably from a RR fanboy). The intake sucks the air in that it needs and there is no shortage of air under the hood. The plenums job is to supply cooler air, not force more air in.
Now if someone starts going into Boyles law about volume/temp then I think I may puke. But in all honesty, I bought the intake for the sound, as I assumed performance gains would be minimal.
(Also, notice the amount of plenum that is still open to blow onto the second filter.)