GTSBoy

A helical is not the best choice for a track diff, particularly if there is going to be inside wheel lift (simply from high G cornering and high roll stiffness, or from hitting kerbs). This is because a helical acts like an open diff when when one wheel is unloaded.

S1 or S2?

If it's in good shape, sure.

Is the suspension at full droop? Try pushing up the lower arm with a jack. Careful not to lift the car off the chassis stands.

Point 1. If you want to do this and want to use that engine, just buy the whole Stagea. You will hate yourself less by getting everything on it all at once and then having to dispose of the stuff you don't want, compared to how much you will hate yourself if you miss buying something and it isn't there when you need it. If you can't afford to buy the whole wreck, then you can't afford to do the swap anyway. 1996 Stagea does NOT have a Neo. It is a version of the vanilla RB25. There is a bit of a halfway-house RB25 that was in Stageas at that time that kinda look like a Neo, in that they look like they have some Neo looking parts on them. But they are not Neo. They have hydraulic lifters and the same old bottom end as the vanilla 25. So, technically, putting that engine and its ECU into an R34 might be challenging. There might be some shenanigans with ABS communication, for example. I'm only guessing, because I've never contemplated messing around with stuff from that era. Sadly, you probably cannot Nistune the ECU (I haven't checked, but R33 era RB25s don't have a Nistune option because they have a stupid orphan ECU). So you will possibly end up contemplating an aftermarket ECU to get it working. You will DEFINiTELY want to take the Stagea's auto trans. The one in your car will die in very short order, especially if you turn the boost up at all. This is true even if you add a turbo to your existing stuff. Hence why I suggest buying the whole wreck.

Boot lip or tail lights.

That's not a thing. Makes perfect sense. The Quaife is a helical diff. A totally different operating principle, in no way similar to a clutch diff. Helicals are the most polite street LSD possible.

You didn't have "no luck". No-one is going to be able to identify the very random problem that you have. You are going to have to do actual diagnostic work. Put a go pro under it and go for a drive. Run it on the dyno. Tape a microphone under the car in various locations until you get an increase in volume. Etc.

good

Why not look to see if the wiring is intact before lurching into swaptronics?

Make a tool out of shim (ie coke can thickness stainless steel) like a little crows-foot spanner than you can slip under the head of the screw and pull upwards (away from the surface it is screwed to) while you turn it with the screwdriver. You'll be trying to get the threads to engage with an edge of something in the hole to provide some drive out.

Solenoid valves are just a coil of wire wrapped around a movable iron core. Put the required volts onto it and the wire creates a magnetic field that makes the iron core move. The moving iron core forces the valve to either open or close (depending on whether it is a normally open or normally closed valve). NO valves are closed by powering them. NC valves are opened by powering them. The failsafe valve is NO and is closed when powered. You should feel it click when it changes state from on to off or vice versa.

Is the failsafe solenoid even opening/closing when you power/depower it?

Well, it has to be. Yes, and, they are saying "This failsafe must be disabled" (My emphasis). And they are saying exactly how to do that.... "Giving the failsafe a switched +12V constant signal will keep the solenoid closed/disabled". I interpret that to mean that "any time the car is running, you want 12V permanently on the solenoid". Ie, power it to close it when the car is running. Have the power switched off when the car is not running.

Well....ground, obviously. A 12V solenoid only works when it has 12V on one terminal and the other side of the circuit (ie, ground) on the other terminal. They're just telling you to hotwire it. Of course, you should not do that without a fuse in the 12V supply. Protect the wire from the solenoid going short.

It's defo what happened. Not the exact same in each case. Remember, this is like the 8th time that BBS has been in "difficulties". Recaro, on the other hand.... we're only talking about the automotive aftermarket part of the company here. The business that makes aircraft seats, bus seats, military vehicle seats, etc etc, is not in trouble. I think the investment company is just being unemotional, purely profit/greed driven and culling BUs that are not making fat profit. The replica stuff won't be helping, because Recaro seats are unarguably too expensive to sell to anything other than a very small market segment.

Both companies bought by "investment companies" and either got broken while being driven to produce higher than possible profit margins, or asset stripping.

R33 GTST rear bearing works the same way as the GTR one - but it's not the same part. You have to get the correct GTST one. You can see the difference between RWD and AWD bearings on this page https://justjap.com/search?q=r33 rear wheel bearing

Yes, well, that wouldn't work even if the sensor was compatible, as the pulse rate would be all wrong.

No. It only typically does it when thrashed (ie on the track), or if it is overfilled, or if there is some other problem in the PS system.

There's no seal on an R34 cap, and as it just clips on, I wouldn't think that you could get it to stay put if you snuck even a 1mm piece of soft neoprene foam under there.

Hence why I didn't dwell on the seal aspect of the discussion and talked about why it overflows and what can be done to help.

Fluid gets hot, expands, comes out the cap. The seal might be old, dry and cracked....but realistically, this is something that has been happening since long before the seals should be able to be considered to be old and dry and cracked. A better PS fluid cooler is a helpful thing. I plumbed the trans cooler from an R34 into mine. Deleted the near useless loop of hardline in front of the radiator that Nissan thought would do the job.

Ever seen a sock on a PS reservoir in a Jap video and wondered why?

When you say this.....is it the stock BOV or an aftermarket venting BOV? If it is the former, then there is no problem, This is normal and desirable. It is not a BOV. It is a "compressor bypass valve" which is designed to do 2 things. The 1st is to act as a BOV, when required. The 2nd is to open when under lightload (ie, vacuum in the manifold) and allow air to flow around the compressor, thus mechanically unloading it, thus requiring less drive power (from the turbine), thus using less fuel, and theoretically (at least) allowing it to spool up faster by allowing the engine to ingest air via the bypass (and hence generate increased exhaust gas) before the turbo gets a chance to pump it. If it the latter, then venting BOVs on stock ECU are arse AIDS and should not be used.