Best bang for buck conversion is. 4g94 2litre engine imo, or a 4g93 1.8l engine
And its also fffffairly striaght forward, whereas other engines are going to be a be a fair bit more money and work
Im actually just finished my 4g15 1.5l engine swap to. 4g93 1.8l, that was my basis swap, and now the g93 is stabalised and everything is worked out im looking at putting the 4g94 2litre block in it as thats a very simple swap from a g93
The 4g9x engines are also very compatible with each other, so u can have alot of different 4cyl engine styles
Can have 1.6l, 1.8l, 2l, then a choice of single cam heads, dual cam heads and mivec heads that are compatibe across the 3 different 4g9x blocks, not to mention a turbo head and setup that fits the 93 and could be adapted to the others ammong many intake manifold options
I think my point of compatability is made