according to my experience, including issues its like
efi cultus>alto>carby cultus
carby cultus gets sluggish, its got a powerful engine but with heavy body and long gear ratios. so it runs ok when moving at 30kph+ but gets over-heated in stop n go.
alto with lightweight body and short gear ratios does better than cultus carby with ac(if a/c rpm increase pod works properly) and it cools quickly too.
efi cultus does best cause engine management is done by ecu on the fly rather than the driver having to push more throttle so a/c cools better with less load on engine and driving experience is good.