The options are
OEM new [expensive]
OEM from salvage yard [you don't know how much life has been used up.]
OEM reman [shops take the core and have the OEM serviced/repaired] <- This is offered at auto-shops, but depends upon quality of parts used
Your OEM reman yourself or ask a repair shop to do it [IMHO the best option provided you damage is limited brush(wear), diodes, regulator [which can be purchased from Lexus/Toyota dealership] and maybe the bearings]

Salim
reman yourself does not require special tools unless you need to pull and seat new bearings.

 

It has been a hot minute since I thought about this thread. So I bought the Terrepower alternator that had something Denso manufacturer, and I got that alternator in the mail, then 3 days later my car stalled out in the middle of an intersection waiting for a light because of a totally unrelated issue, which because of this whole fiasco, I thought the alternator died and the car just suddenly dropped dead because it wasn't turning back on. So I had it towed back to my house and my dad installed the alternator while I got a ride in the back of a cop car back to work to finish my shift.

Turns out I later found out, there is a ground bolt on the left side of the intake manifold that has 2 ground wires on it. That got loose and the wires were grounding off of each other (?) and that caused like 20 codes and the car having all sorts of issues. As well as that probably was the reason my ECM relay got shorted out as well.

Anyways, I replaced the alternator with that aftermarket one I bought and going on 2 months ish now, it seems to be working just fine for me.

(Edit: didnt read my last post and forgot I already mentioned all that)

Now besides all of that something weird is happening as well.
Y'know how when you start the car, it cranks for like 4 cranks then starts right? Well after all that happened, when I start my car, maybe 1/20 starts, it cranks for 2 times then nothing, no battery stuff, no engine start, nothing. Then I back off and crank again and it works like nothing just happened. It appears to be happening more often recently to (maybe because its cold outside now?).

I doubt its the alternator causing that, But the car drives perfectly with no engine codes besides that one issue. I replaced the ECM relay with a $20 one from autozone and tightened the ground bolt, so I have no idea what it could be.

 

Maybe the starter solenoid is failing. As these cars age the contacts wear out. Usually that would produce just a "click" but maybe this is another manifestation of the problem. Example rebuild kit and video here: https://www.nationsstarteralternator...uild%20kit.htm

 

Just an update, the starter contacts were going out and I have pictures of how bad they are but I don't feel like finding where I have them so...

I bought these contacts from amazon and they were an exact match so use this for any 1999 rx300's starter contacts replacements.