We can manufacture a superlight 3.5" tailshaft for you, as used by the two WTAC winning Skylines - Xtreme R32 GTR and Integrated Motorsport R34 GTR.
More details here: http://alphaomegaracing.com/p/143/c/71/All-Products/ALPHA-OMEGA/MONSTAR-Tailshaft-GTST-GTT-RWD.html