I evaluated both the 3" and 1" relocation. I elected to go 1". This is because it got the spring out of the way without needing to modify the wheel well or the frame rail. With this I change I have a 10" wheel with a 12"/305 metric tire and plenty of room everywhere. I have mocked up a 13.5"/335 metric tire that appears it would fit with a wheel with exact backspacing.

If you look at the stock wheel well, there is around a 1-2" space between the rear edge of the well and the frame. If max tire size is the goal, splitting the well and installing the spacing strip, the USCT kit has this piece, would gain you that last 2 inches. In this case, a 15"/365 metric wide tire may be able to squeeze in there.

Beyond that, you have to modify the frame rail.

Don't forget we have a lot of the Direct Connection info along with some other members feedback in the Tech Section: http://www.moparts.org/Tech/Archive/rearsusp.html Look at the Rear Suspension Info, Spring Relocation (rear), and How to fit BIG tires on a Cuda.