Hi Arno,
also from ZA here, don't use SA as the guys on the southern side of down under already uses that...
While I know that you are more inclined to go for the 2.0 option, I can only tell you what I've experienced. I'll try to make it as unbiased as possible.
My bro in law built a 1200 sedan(which is basically the same thing as the ute from the front doors forward), with a CA18DET. There is no space left in the engine compartment for much else than the engine and some pipes, and it seems to be far more work to do than say the 4A-GZE.
It involves changes to the transmission tunnel, cross member and engine mounts. The parts for these combinations(say the CA18DET) are also less plentiful, and most definitely far more expensive when you can get them.
To build a sleeper with the CA18DET/SR20DET, I'd say would be slightly more difficult, than say the 4A-GZE. This is mostly due to bulkyness. However as some excellent examples on this site has proven, the bigger engines can be hidden quite cunningly.
On the circuit I see a lot of 4A-GZE/GE's packing up, and not many CA18 and SR20's. But that may simply be because there is an overwhelmingly larger number of the Toyota engines installed.
We don't have the same problems with getting the large engines registered and road worthied, as our counterparts on the other side of the world. The brakes has to work, the steering must turn, there must be no oil leaks, and suspension components shouldn't have play. That's it, other than that you can probably fit two 5.7l V8's to a 1200 and they wouldn't mind.
I've seen a Mini fitted with a V8 running and roadwortied before...
It basically boils down to how purist you want to be, and what you want to achieve in the end.
My personal preference for the 1200/1400 sedan/ute is the Toyota 4A engine range. But if I ever build another car, I might decide to use a larger body with a SR/CA.
Cheers
Francois