what you are doing is changing the transfer case yoke (thing that attaches the driveshaft to the t-case) from a slip yoke, to a fixed yoke, hence the name slip yoke eliminator.

The hack-n-tap is one approach. here you cut off part of the output shaft on the t-case, (the hack), and then tap threads into the end and bolt on a fixed yoke.

Advanced Adapters, and JB conversions are two vendors that replace the main shaft with a shorter shaft designed for a fixed yoke. Both come with a new rear tail cone for the transfer case. This approach seems to be stronger, and results in a shorter overall transfer case which allows a longer rear driveshaft -- which is a good thing.

I have the JB conversions. I think it is comperable to the AA. Some like JB better, some like AA better. I don't see any difference.

JB Conversions has a new short shaft setup that allows an even longer rear driveshaft that previous setups. I've read about it but that's about all I know.

here is a link.

http://www.jbconversions.com/pages/products/np231/np231j_short_sye.html#comparison

If I were doing it all over again, I would likely go with this new super short SYE which would allow a longer driveshaft. an inch longer DS helps the angles abit.