All this Gas helps Ruredi on information ;) he needs it.
Stu I think if your Z18et block is as tall as the L20b then
you probably have Z20E conrods which are 152.5mm otherwise
with 145.9mm l20b rods you have way too much room left with
the L18 crankshaft unless previous owner used tall piston.

Rb30 forgies leave 2 spare for overboost or damage :)
SR forgies have the wrong pin diameter for L rods ;)

http://www.youtube.com/watch?v=AwV7ZTyHY4M