I have. Not all engines will be bolt on swaps. Local Cuore comes with N/A 850cc ED-10 engine. You can get any E-series engine for replacement, but best to get a 1000cc EJ-VE Duet engine or 660cc EF-DET Turbo engine.
I have the EF-DET Turbo installed. Bolt to bolt swap, you can even use the existing gearbox. Gem of an engine, much more powerful and fuel economy is improved too although I can't tell you by how much as I never bother measuring economy. EF-DET is usually found in the 660cc Terios Kid.