Leigh the emission gear the SR20DET is superior? :P
Twin spark plugs have a great option you can run them in different configurations to suit different ignition requirements and fuels not just emissions. eg Alfa, Mopar.

George Fury had a choice of engines as far I recollect Feral teachings and the turbo L28et and FJ20DET where supposedly considered in the 280zx and 200sx which have superior chassis but in the end the import IRS (it was not what you call factory IRS if you looked under that thing!) bluey with Z18et at 32psi was the cream for handling over 50kg heavier FJT. Someone w/ better info on historical choices there might know? but it might be snowball info. Wheres Feral when you need him! Feral is a pro Zet dude.

The L and the Z are the same engines really just different timing cover and crossflow head nothing complicated. Full counterweights on L18 and L20B cranks are superior but not essential for the rpm boost without lag needs.

The L with all the gear crammed on one side is not pretty. The Z has sodium filled exhaust valves and exhaust ports that with porting can dwarf most 4 cylinder 8v heads. Plenty of meat there for boost, big ports & valves = winwin.

Simon is making big power with the A12 but theres alot of mula behind it and development that can be described as blood sweat and tears but I myself respect love the A again after his efforts. Did someone whisper A18T series? bring it on.

My Uncles TRX bluey with LZ20et had notched 86mm bores +4mm bigger inlet valves instead of 42mm stock, +2mm exhaust over 38mm stock. Its suposedly inferior performance oriented pro swirl design chomped his brother (my old man) in most duals vs same psi and same T3 in well tuned FJ20et. Dad even put the running gear in a lighter 1600 shell but still lagged on take off and midrange where it mattered most. When they swapped cars results where pretty much the same.

Stu, maybe you should start a thread like Simon on how much your LPG will make with the Disco spud and the winner getting a ride on the track but I reckon your selling yourself short and 200hp atw is a conservative figure.