Which typy of engine will be for my Suzuki jimny 1,3 m13a with VVTI

Which engine would be a good swap for my 2006 Suzuki Jimny? It currently has a 1.3L M13A with VVT. There are many potential engines that could be swapped in, but I need to know which one would require the least modifications. Can you tell me which car and years I can get an engine from that would require minimal modifications? I'm considering the SX4, but which one? Or perhaps the Grand Vitara II 1.6? What should I look for when buying such an engine? 

What is the reason for the swap?

The easiest swap will be the exact same engine, an M13a with VVT, so if what you're looking for is to replace a worn out engine, that would be the way to go.

If you are looking for hp the m16 is the easiset. Donor engine should be also VVT and from the same period so the ingition and wiring is compatible for the least amount of trouble.
There are differnet specs and model names for suzuki cars in differnet markets but I guess european ones are mostly the same.
I used a Liana long block and reused the m13 intake, exhaust manifold, oil pan, valve cover, dip stick, auxhiliarys, wiring++ mostly everything except the m16 engine block and top.
the injectors are the M16's.

by googling "bigjimny m13 m16 engine swap" you should find many threads on this forum on the subject.

I once met someone who had put in a M15A from a Swift. He said the engine is identical apart from a longer stroke.

M15a is more available and cheaper than M16A 
Only around 8 bhp difference 
And 13,15 and 16 all use the same head
M16 throttle body is bigger than the other 2
 

Well that varies between markets from supply and demand, Dunno if Marcin here is Poland-based but here in Norway the Liana is a much less desirable car than most other suzukis so prices for the Liana M16 engine is way less than that of a Swift. Used engine prices for a Liana M16 is often half of a Swift engine.

And there is no m15's of the correct age/spec at all in Norway, not sold here.

I have no idea of the European markets though.