Found this through a Google search on SupraForums and no mention of it on HybridZ.
http://www.supraforums.com/forum/showthread.php?t=477519
Basically, for ~$80 you can avoid the possible screw-up of fabricating your own shifter extension if 1.125" of additional length does it for you. From pictures I've seen of a couple R154 installs here, that may be all we need. I may just cut up the stock one anyways because I imagine I'd like to have it sitting in the stock shifter location; or, rather, as far back as possible while being able to retain the stock center console and not chopping it.
Also, if you read further down the thread, there are a lot of guys who say this shifter extension will not be enough for the MKIV guys as the thread starter suggests. I think it's the newer Soarer R154 that has an entirely different and much longer (4"?) shifter/extension housing than the MKIII R154.
Excerpt of important info in case that thread disappears.
Then, further down, a guy responds with the parts explosion of the later Soarer R154 with the much longer shifter extension. I haven't figured out if it's bolt-on, but it has a great deal more parts and I imagine is consequentially equally more expensive. I may have to look into it - http://www.supraforums.com/forum/showpost.php?p=5824871&postcount=8