Synonym for a heavily modified or self-made car or thing

I'm looking for a word for the following things (they may be the same, or have different words):

  • cheap car modified or constructed by owner using scrapyard and low-end tools (and thus having certain "quality")
  • cheap car with expensive and redundant modifications (golden bumpers?)
  • a regular car which has almost all parts removed and/or replaced to make it more lightweight and faster up to make it unusable for everyday use
  • not a car but technically complex thing fits any description above

The only words I've found are junker and jalopy, but may be there is more?

EDIT: Commenters asked me to present a sample sentence, but unfortunately I'm trying to find a name for a blog, so there is no sample sentence. May be "%word% Lab" or something.


I suggest customized (BrE customised). Lexico has

customize
ADJECTIVE

Made or done to order; custom-made.

Modifying or customizing a vehicle has also become a trend among car enthusiasts nowadays.

Every bike is unique because everyone customises their bike to reflect their individual personalities.


Similar to this is the term custom car. Wikipedia has

A custom car is a passenger vehicle that has been either substantially altered to improve its performance, often by altering or replacing the engine and transmission; made into a personal "styling" statement, using paint work and aftermarket accessories to make the car look unlike any car as delivered from the factory; or some combination of both.
Batmobileenter image description here

And then there is the kustom car in a particular style, see Wikipedia.

Kustoms are modified cars from the 1930s to the early 1960s, done in the customizing styles of that time period.


I think you'd be hard-pressed to find a word that perfectly fits all four of your descriptions. That said, one that comes to mind for me and which may get you close is jerry-build, which can be used as a noun or a verb meaning:

jerry-build: to build cheaply and flimsily (Websters)

For the record, though, I'm also a huge fan of @Weather Vane's more specific suggestions for your examples two and three: pimped and stripped down, respectively.