Transmission Tunnel

The first half of March 2011 was spent tacking the transmission tunnel into the chassis:

This is where the first change to the book is required.  In the sierra chassis the tunnel is straight all the way to the back.
The input to the diff on the MX5 is offset to the drivers side, which meant the tunnel had to be flared out at the rear to accommodate it.
Here's the dimmensions I used for the SB4 rails in the seat back, which set how much the tunnel is flared out: