The stock setup that came in Khyber was the g10.
It was a 3 cyl. SOHC engine generating power around 50hp.
g13b is a 4cyl. 16valve DOHC engine producing around 130hp.
This engine came in international market in 80,s in Suzuki Swift.
g15a is a 4cyl. 16valve SOHC engine that came in Suzuki Esteem/Baleno, Suzuki APV and in Suzuki Vitara.
This engine generated around 100hp on stock internals.
Both the g13b and g15a engines are a bolt on swap with minor alterations in Khyber.