taking apart the dash to get the head unit out takes less than 2 min
if you was closer id trade you straight across for my K&N CAI for your stock set up, im wanting to do a snorkel so i need a "sealed" air box... K&Ns gotta go
FYI - I have a Volant CAI that I'm taking out and going to a deckplate modded stock airbox. Those CAI's make way too much noise, makes the 4Runner sound like it's breaking the land speed record, but instead it's only going about 25mph.
Unless you like tons of intake noise, just do the deckplate mod, you'll thank me later.
14'' muffler gonna be real loud unless thats what your after