Datsun Roadster Forum-311s.org

There are quite a few captive nuts throughout the interior. If not filled with a fastener, sound like broken glass in the bottom of the door.
What type of noises are you hearing?

Lots of bangs, its kind of hard to describe. I can visually see the hood shakes when going over uneven pavement and from the sounds of it, its coming more from the passenger side more.

Get a swim noodle, cut chunks of it to use as wedges to isolate things and go for a drive. It will take some time, but you can eliminate a lot one panel at a time.

Considering the aforementioned lowered suspension you may indeed be hitting the bumpstops? Id look over the suspension real well in addition to the other advice offered.

Oh and welcome, nice car! You are lucky to know so much history of whats been done to it by exit64

Also one of the first things my son fiddled with on my car during his first inspection was the twisties and posties, lol.

Check the bumpstops. they could be too short, causing the tie rods to hit the frame. That will make a banging sound.
Also check the upper fwd A arm bushings. if worn, they will rattle.

Upper arm spindles were replaced with NOS from Nissan at the same time that I did the lower ball joints. There was always a sound that I could never figure out coming from the passenger side that sounded like loose spoons in a silverware drawer rattling together. Drove me nuts. That car was stock ride height when I owned it.

Now that's a better way to describe the sound "sounded like loose spoons in a silverware drawer rattling together".
Given it's audible going 25 over a manhole, and Mike's note on the a-arms - I'm going to try SPL310s suggestion and use the swim noodle/weatherstripping first.

Adding weather strips to hood area made a big difference. Removing the extra bits from the trunk helped some too.

The windows are rattling, probably need new rail hardware. Incremental improvements are making the driving experience more enjoyable. Fun car !

Hopefully I get up to mike young's shop in the next few weeks and learn a thing or two.

the rear vertical window rail fractures at the mount tab. if you remove the screw and the tab falls to the bottom of the door, you know its broken.