I've heard of a 6 cylinder engine in the back of a mini van. Some engine swaps are for craziness, some for other reasons. Interestingly, it's not often that an engine swap is downsized, so I'll share my recent engine swap I did. This is one which should have been offered by the manufacturer - my wife's 1990 Toyota Sera had a 1.5L engine which was pretty good with 81kW, but behind an automatic, it wasn't quite right. So I took a 1.3L Turbo engine from a Toyota Starlet GT and swapped it in. The engine is the same "E" family, has same engine mounts and even 99.9% same wiring loom! But the boosted engine has 20% more power @ ~100kW and now it's nice to drive despite that tiny bit of turbo lag and drop in engine capacity. Fuel usage is about the same too.