Just replaced my power steering pump so I thought I'd add some info here.
Do NOT get an 85 200SX Turbo (CA18ET) pump. The DET pulley will not fit.
Do NOT get an 88 Pulsar NX SE (CA18DE) pump. It's mounted on the other side of the engine due to being in a FWD platform, and will be upside down on a DET.
Get a 91 240SX (KA24DE) pump.
It fits the CA bracket AND tensioner AND pulley. The KA tensioner looks like it could work too, I just didn't bother since the CA one fit. I swapped the low pressure hose fitting over from my CA pump, but the KA one is usable if you just reroute the hose. Also, I used the KA banjo fitting thingie so it would be all OEM and stuff. You can see it in the second pic. It did require hacking off part of the CA bracket (you can see my crappy job with a hacksaw in pics lol), or you can use KA bracket or you can just use the stock CA set-up or whatever. It doesn't really matter. THE KA24DE PUMP WORKS
~~~pics~~~
Notes:
Replace copper crush washers if you don't want leaks at the high pressure joints. KA fitting-to-pump banjo bolt requires M18 copper crush, easy size to get at parts stores because they're used as oil drain plug washers. The banjo bolt connecting the high pressure line to fitting requires M16, which I couldn't find locally. BUT Harbor Freight sells a copper wash assortment that has an imperial size that interchanges. Like 6.99$ for a whole set. Go for it.
Also, be sure to use Dexron ATF in the power steering system. This is what Nissan specifies in the FSM.
My stock belt fit with CA pulley, tensioner, and KA pump. Don't know if stock belt will fit with KA tensioner, didn't try it.
But yeah. If your power steering pump goes out on your CA18DET, get a KA24DE one.