Alternator Bosch or Motorcraft

Stick with a high quality oem replacement alternator; VW installed a number alternator oem brands (bosch, Valeo, Hitachi, etc). My 2002 New Beetle Turbo S; had a Valeo 120 Amp unit installed, I had a hard time finding a Valeo unit, so I went with Bosch and so far, I have not any issues with it but the body of the alternator, was slightly bigger, so the wiring harness, was a bit of a tight fit.

You can get a Bosch alternator for a KA and swap the pulleys

Any time I see overvoltage faults I replace the alternator. Check the charging voltage and confirm that it's charging higher than 15.0v (it may happen only briefly under some conditions). If it is then unplug the connector from the alternator. That should default it to 14.3v. If it still overcharges then you've confirmed a faulty alternator.

Lucky for us, the Alternator was in fact faulty (it was a Bosch btw) and that the previous owner replaced it a few months prior, meaning it was still under warranty.

Bosch is a great aftermarket option.

Yes, if it was from an OEM supplier to Lexus or the auto industry, such as Denso (1/3 owned by Toyota/Lexus), AC Delco, or Bosch, but I would not buy a mystery brand, especially not a rebuilt, because I don't know how much they get rebuilt or tested.

I bought a Bosch rebuilt alternator from ECStuning and installed it last night. The light however has stayed on.

I wasn't crazy with the AC Delco (GM) alternator conversion when I used it on my MGB engine. The Bosch ones seemed to be a little better designed and easier to convert, plus they looked simmilar to the Lucas ones.

A friend had a rebuilt bosch unit that he lent me to try and that too doesn't put out any voltage.

We've had all sorts of problems with Bosch reman alternators. They worked really well until Volvo put the alternator on the CAN network. The reman ones have a ton of trouble making the right charging voltage.