Don't over think it just use the picture above for reference and free hand it. I'm 99% sure that when going down the assembly line they just opened the door and put them in the general area where they needed to be. I looked at a bunch of pics I've collected over the years when doing mine and...
The link above is what I would go with. Just remember on a GNX there is a hole drilled through the A/C duct for the cable to have a straight shot to the back of the speedometer witch you will have to make. Do a search for GNX dash install and you will see what I'm talking about, it uses a piece...
Here are some links to what you need
https://www.kirbanperformance.com/product/44112/Reproduction+FRONT+LICENSE+PLATE+BRACKET+%237535.html
https://gbodyparts.com/front-license-plate-mounting-hardware-p-1134.html?osCsid=1f85cbdfd63b8edda538733309e31a0d
I'm using a hydroboost from a 1998 Astro van witch I'm pretty sure has the same bigger piston as your truck unit, a master cylinder from the same 98 Astro van but with a fluid reservoir off of a 95 Saturn SL (if I remember correctly), S-10 Blazer dual piston front brakes and a stock...
Better / modified pump should help but have you checked to make sure there are no kinks or sharp bends in any of your lines? if your return line is a T fitting from the steering box to the reservoir it could be causing a restriction witch will hurt both braking and steering feel, A better option...
Those are factory plugs. My car had them too but most of them crumbled when I took them out before paint. I don't see it being a problem if they are left off but I would definitely put them back on if I could find new ones.
They are modified in the back and a little in the front for turning clearance but they do have a hell of a lot more room at the top for bump clearance too.
Like stated above all that really matters is if you like it but sounds like you might me having second thoughts if your asking the question. I give it a thumbs up especially with the 18" wheels but If it was my car I would like it about 1/2" higher
I wonder if it was a internet or phone bidder that bought it? If it was I think they might be a bit disappointed when they get it, then again I might just be too picky. They claimed 100% stock but those rotted out mufflers were definitely not original along with the cheap chrome clamp on...
I was in Palm Beach and got a good look at it also. Overall it looks good but it definitely needs some TLC. Some of the stuff I noticed is the exhaust is trashed, it has the wrong radio in it (not a concert sound radio), side window belt moldings are all cracked up, who ever put the grill...
Found these on Caspers electronics site
http://www.casperselectronics.com/cart/index.php?route=product/product&path=7_53_54_10_13&product_id=299
http://www.casperselectronics.com/cart/index.php?route=product/product&path=7_53_54_10_13&product_id=298
You can get just the terminals from them...