e-hata mitho khan have a bunch of these, plus chah sultan glass factory road, but if u want some very clean piece on premium price try searching for carriage factory road opposite old afghan basti, there was once a shop selling a half cut of baleno with 1.6 auto tranny engine, and was asking arround 4 lacs for the whole half cut.
G13b is expensive because of less supply, engine can cost u around 85 thousand to 1 lac. depending on fankari of khan sb.
g-16 is comparatively cheap and have heared few guys replacing J18/or M18 as well.
these engines were in ample supply in Shoba -peshawar but now they are reduced in numbers because of less suply from torkahm and shifting trend to newer 1000cc or 660cc engines.