Hello, welcome to YotaTech.
You can fit 33s now under the FJ in stock form if you keep the factory wheels which have a great offset and tuck them in close.
However if you go with aftermarket wheels, they will stick out some, and it is a good idea to do the "body mount trim" procedure.
http://forum.ih8mud.com/showthread.php?t=137655
I run the OME 3" lift with stock size tires, only in muds.
I am stepping up to the 33s later on, not sure if I will need to do the body mount trim or not since I have the lift.
I have seen many pics around the 'Net of a stock FJ sitting next to one with the OME 3" lift on it, quite a difference.
Myself I think 6" is pushing it for an IFS rig.
This woman here was rubbing with 33" tires and a 3" lift, but that was due to her choice in aftermarket wheels which stuck out a lot further than the stock wheels.
http://forum.ih8mud.com/showthread.php?t=115308
As far as how I like the FJ, I have absolutely zero complaints on it.
You mentioned you have seen some good vids off road, here are two FJ Cruisers on Hells Gate at Moab.
One is stone stock right down to the factory tires.
Those vids can be found in this same section.