Neverdone

Seems like the "soft" mounting in the back of the diff would only affect it in the fore and aft direction. Having no isolation on the front of the cradle (where the front rear suspension bar bolts to), and having isolation on the rear of the cradle (where the mustache bar usually bolts to) could affect things. How much will it affect the overall dynamics of the vehicle? How will that affect NVH? How will that affect the life of the cradle/isolators/suspenion links/alignment/etc? I don't know.

How old are your tires, and when was the last time you had your wheels aligned?

there any reason you didn't extend the bracket down in front of the mounting "ears" of the back of the diff down, so that you could mount the diff straight to it?

Man, that car is in the air and the gap between the fender and the tires looks minuscule. Obviously this is also because they chose wheels and tires that are entirely too big...but the quality of the flare itself seems alright.

Hybrids have almost always been a stop-gap while the battery industry invents the battery/charge infrastructure that it needs. The only benefit hybrids have at this point is slightly cheaper cost, and the ability to travel many hundreds of miles in a single day. Unless you're making a semi-truck that needs all that range and carrying all the batteries for it would be insane/expensive, I don't see the point in going hybrid. If you're going to put all the work of getting an electric motor to run in your car, you'll want to just axe the ICE engine all together. However, if you're going to look further into this, know that you're about on the same page as where current OEM's are right now in terms of technology. You're discussing making a P2 position hybrid. Would you like to know more? https://x-engineer.org/automotive-engineering/vehicle/hybrid/mild-hybrid-electric-vehicle-mhev-architectures/

Looking great! Is that an OEM part or some after market that you've plugged what looks like a water temp sensor into, that's attached to the radiator inlet?

I'd possibly watch out for interfering with the front tire when the suspension is fully loaded, but that's about it.

making a mount for it would be easy as it's just two flat bars that enclose the ear mounts of the BMW rack will actually lower the rack down to make more space for whatever you need. You need to shorten the inner tie-rods about an inch (from what I've read anyway) and Subaru Forester outer tie-rods mount to the knuckle and inner-BMW rods. Add in that they're super cheaper and widely available, I'm surprised more people haven't looked into using them sooner. Looking forward to your progress!

No. Nissan named two differentials the "R200". You'll see people calling them "longnose R200" and "shortnose R200". The longnose R200 came on the 280z, 280zx, and Z31 300zx. The shortnose R200 came on a bunch of Infiniti's in the 90's, and the S14 & S15 and maybe some other vehicles. Before you ask, I don't believe you can just swap the LSD from a shortnose R200 into a longnose R200 without a buncha work. I could be wrong, and as always, almost all of this info is out there already.

You gonna use the BMW steering rack, or go with a Subaru or something?

As fun as a 2000 mile highway only drive that would take days to complete, in just one direction, in a 50 year old Japanese car sounds to you... I can't blame him for wanting to ship his car and just fly out there.

Champion makes good radiators. https://www.championradiators.com/Datsun-240z-radiator-shroud--Chevy-Combo-1970-1973-

You'd need the ring and pinion out of a non-tow package Nissan Titan, or an Armada or something. They run a 2.94 final drive ratio. I've personally never done it, but changing gears is possible. Why do you want to do this?

BMW uses a press in bearing and wheel hub flange instead of an easy to replace and far better self enclosed wheel hub/bearing like damn near everyone else. You'd have to weld on a tube that's within tolerance of the rear wheel bearing to be able to press it in if you want to use BMW parts. Or you get 930 CV's and make custom length axles that bolt to the output flange of the BMW diff and make a custom companion flange/adapter that works with the stock stub axle. EDIT: Actually, the E39 uses bolt in wheel hub bearings, and has axles that can bolt to an M3 diff. Sooo....maybe? Would probably have to do work dealing with the brake caliper mount, but it's possible to go full BMW if ya wanted to.

I'd be more worried about the brand new head you're gonna need to design to push all that air through it over what ECU you're gonna use. I'm not saying it's impossible to make 600 horsepower on an L28, hell anything is possible with infinite money, but it's realistically, impossible. Use a different engine.

Ok, I see what you're talking about. You're just mounting a spacer under the sway bar. Most people affix that by just running the bolts through it and that's it. However, you shouldn't sandwich dissimilar metals together. That creates rust. Look up galvanic corrosion if you're dead set on using those.

Don't use glue on anything structural in a car.

What are you asking?

Don't let him weld anything of yours.

It's steel. This isn't Medieval times. It's not a cast iron skillet or something.

As "ridiculous" as an adapter might be, cutting and welding is a lot more scary for MOST people. Don't give up on it just yet, and there might be a way of doing it that isn't too crazy.

Man do I hate how Nissan didn't choose to re-name the short nose R200... 1) You've obviously gota be talking about the shortnose R200 that came with the Q45/350z/370z. This is because your car currently already has an R200, albeit a longnose R200m which has a completely different carrier, and in the 280z, was an open diff. 2) The only question anyone should be asking is, "What do you mean by 'viable'?" Will it work? Yeah. Will it break? Not unless you're gonna be putting way more power then what came stock and using some incredibly meaty tires. Is it the best diff you could use? There is no best. 3) Technotoy tuning sells a conversion kit to use the shortnose R200, which also uses custom uprights to use plug-in axles, as opposed to a stub axle+companion flange set up which the S30 came with. There's lots of befits that that rear end conversion also brings, but it's at no small cost. If it is worth it or not is completely up to you. That should answer the questions you were asking.

What are you trying to do? Wouldn't just using a different transmission be vastly cheaper and easier?

I think you're gonna find a lot more info on people swapping VK's into their 350 and 370z's. However, most of the information you'll glean from them applies to our cars as well. https://mckinneymotorsports.org/vk56de/datsun-240260280z-s30-vk56de-motor-mounting-kit This link is very confusing as it clearly says it's for a VK56 mount in a 240z...yet when you click on it, it brings you to a VQ mount...maybe it's the same mount? I'd shoot them a message if you want to use their parts for this swap before spending money to make sure it'll work.

Are you currently running a Z31 front hub or some custom hub? Those rotors are 5 lug is why I ask.