Since you asked about the hack and tap, and I just typed up a response in another thread on this topic, I'll repost it here:
It's a poor design. More a band aid than a fix. Look at any other SYE on the market and you will see that the rear output flange, when tightened down, is sandwiched between the output shaft inner bearing race and the front of the flange. There's a reason for this- splines are not designed to support the forces created by a spinning drive shaft. Mine worked great with 3" lift and 31s, for 2 years. Then the flange became loose on the output shaft, and had to be replaced. At that time I went up to 5.5" lift with 33" tires, and the new flange lasted 6 months. Rather than buy a new flange every 6 months, I called Tom Woods and did it right.
3 years ago I was on this website supporting the RE hack and tap, but now I know better. It's nothing against RE, because everything else I have bought there has been excellent quality and value.