Hello, I'm curious to find out if there are any legal concerns regarding custom building your own car. I'm considering building a simplified Morgan style three-wheeler using a mid-sized motorcycle engine and hugely extended and widened bike frame with traditional wood framing for the bodywork. Is it legal for me as a foreigner to build my own car here? Also, are three-wheelers considered cars or bikes here, or both? Thanks in advance for your help.

Not sure how it pertains to bikes.  But for cars any "special" needs to use the original chassis ( with the chassis plate/number ) So a rebodied car based on VW beatle floorpan is okay. But swapping the beatle running gear into a sports chassis isn't. I'd had similar ideas to you as the Morgan is only a V-twin with a mazda mx-5 gearbox. Dunno if possible to lengthen and modify a bikes frame and still use the rego. Lots of changes to turn a bike into a three wheeler. Dunno how much of thevoriginal frame would need to remain or if once modified it becomes impossible to register