I turned my MS CAI into an SRI today and had to get the filter/water shield out. I did it without taking a wheel off or going through the wheel well. You just take the intake apart pretty much. Take off the intake temp sensor thingy first, then unbolt the CAI's support on the second pipe. Then after that undo the hose clamps that keep the first and second pipe together. After that you need to undo the hose clamps for the first pipe, after that's undone just move the first pipe out of the way a little, you don't even need to unhook anything from it except for the MAF connection. Now that the second pipe is free to move around just move it around enough so that you can put a ratchet or wrench on the two bolts that hold the water shield on. After they're out push the water shield off and pull the 2nd pipe out. That should be it for getting it out without taking off the wheel or going through the wheel well.
It took me about 10 minutes to figure out the best way to get it out since I stupidly didn't install it myself. I'm pissed at myself for letting the dealer do it when it's so easy. I'm pretty confident that I could convert it back to a CAI in less than 15 minutes. It's pretty damn easy to do once you figure it out. So if you do it this way it may take a little bit longer to remove it the first time but putting it all back together after cleaning the filter should be a piece of cake.