I bought my X-6 second hand,with the OG 3 gear tranny,then bought the 'Total 4 Gear Update Kit'.
What an awesome car...I've since driven stock B4's and the difference is night and day.
Takes a little tinkering to get them to jump level,or with the nose slightly down,but it's all good!

Here's my 4 gear X-6.
I gotta buy a new body and paint it up in my colours...