I found my receipt from Summit Racing: part number AVM-21 2039 DK. I'm pretty sure our cars use a 3" diameter intake tube...the length of the filter is about 9", and the diameter of the filter at its widest is around 5-6". It fills that airbox, and I had to space the airbox out from the car .5" or so. I used sheet styrofoam for that. I believe I also removed some of the insulation at the firewall and from the side of the car inside the airbox. With those mods, there is plenty of space for air to circulate around the filter providing 360 degrees of flow. I'll see if I can come up with a photo.
To answer your question regarding removal of the stock air box, yes it could be a pain "if" you choose to do it by direction. In my case, I had no intent on letting the stock air box collect dust in my garage, so I took it out in pieces; easy and quick. I choose not to loosen the intake manifold and present the opportunity for future leaks. The installation is easy and there is a good write-up on the Evo site for the DIY.
"The existence of the flamethrower is evidence that someone, somewhere once said 'I want to set those people over there on fire, but I don't want to have to walk over there to do it.'"