Which oil pump would you get for a bnr32 ?

[Reality]

The oil pump issue isn't just the gears and collar. There is a harmonic (or vibration) that naturally occurs in the RB that can rattle the internals of the oil pump as well. I believe they are most predominant at around 3000-3500rpm and 7000-7500rpm. Your best bet is to have the bottom end with the clutch assembly your going to be using balanced and obtain an ATI dampener. The factory nur block or N1 motor is good for 500whp and is still just standard stock internals. The engine comes from the factory balanced with and N1 pump and collar. If built correctly stock internals will do 500whp all day long reliably.

The best pumps to get are,

Tomie
HKS
JUN
NISMO
GREDDY
others...

Tomei and HKS are the beefiest with JUN and nismo being next in line. I have heard of more greddy pumps failing than others but its still really uncommon and is usually the result of something other than the oil pump.

You can also do 500whp for a lot less than 30k... unless your including the car as well :P

[cobrAA]

I already have an ATI fitted on my car.

[Zacho]

Just remember the weakest point decides how reliable/strong a car is. Don't go putting a dry sump oil system on a car with a factory fuel system lol.

Why not, dry sump FTW. Kidding, just a bad example there I always assumed the harmonics of the RB was related to the common cracks in the block.

Personally I would go either JUN or nismo (or an equal reimax frankenstien).

[GTR-Dad]

Flow rate is another variable to consider. The OEM, N1, and Nismo all flow at a similar rate, with the Nismo being the 'strongest' of the three. If you get in Jun and Tomei, you get a strong pump that also pumps more oil per rev. This is all good unless you get it pooling in the head and sucking air from the sump. Then you wish you hadn't been so eager to upgrade the pump...
Some guys bore out oil return galleries, others fit an external return line on the back of the engine, and still others just drive. I suspect the guys with oil return issues are probably revving very high. I've got no direct experience with anything but running a Nismo pump up to 8000 rpm. It's been good.
Oh, and the oil pump cares more about rpm and torsional shock loading (harmonics) than it does about horsepower. Crank dampener FTW.
Dan