I am just starting a re-power of my Haynes with a gen 4 3sgte motor and 6 speed altezza box.
So far it looks like the gearbox will fit into the chassis without any tubes being trimmed. Also, the motor will fit under the bonnet without needing to put a bulge in it.
The sump is a tin item from a gen 3, with a 5sge oilpump ( built in relief valve). I will need to chop about 1 1/2" from the sump, but there is plenty of width to make the sump wider.
The inlet manifold will need a trim as well.
http://www.lotus7.co.nz/forum/download/file.php?id=591
http://www.lotus7.co.nz/forum/download/file.php?id=502