You can do a "test fit" by pulling down the arm rest, resting your elbow where it naturally wants to be, then - with the shifter in neutral - blindly (with out looking) reach forward and pinch the shifter rod using your thumb and index finger. That's where you cut. The universal fit AutoZone knob clamps on w/ 3 allen screws and also adds about 1" to the height.
Like I mentioned, I cut it twice just to be sure I didn't reach the point of no return.
In addition to the taillights, I have at least one more ultra cool mod that I'm sure no one else has done yet. It's high profile but only costs about $30... and alot of trial and error so far <img src=icon_smile_tongue.gif border=0 align=middle>