The main obstacle you will need to overcome with any of the cars you have chosen to research is the owners of those cars.
All of these cars attract owners that are young enough to want to drive them and unfortunately want to personalize them.
While tasteful Modifications once done can make the car look good, or sound good or even make more power. what kind of horrible workmanship will you find lurking just waiting to be discovered at the worst possible moment.
a car that was highly modified by a hack wanna be shade tree mechanic is normally easy to spot and avoid.
What is not so easy to spot and avoid is work from a lazy uncaring line mechanic or mechanics that have over the years have decided to cut every corner they can by not rerouting the wiring harness correctly after doing a cylinder head job or leaving bolts out, not torquing bolts properly. chopping away at vacuum lines and wiring, bypassing nearly anything they can so they can move on to the next gravy job.
The worst part is when the cars were new or new enough to have every GM part available cheap crooked shop owners even GM dealers would put in junk China made parts without the owner being any wiser yet the owner got charged for a OEM part at a OEM part price.
MY point is, your question is not a fair one to any of the cars you have listed.
All of these cars when produced new started life just as reliable as any other car from that era
1981-1992 are examples of cars that normally do not have a resale value high enough to warrant a pebble beach restoration, finding parts for these cars can be difficult to impossible depending on what part you want.
If your lucky enough to get one of these cars that was a garage kept one owner low mileage with a complete service history and clean title, you may have a chance of ending up with a decent car that has low power and a quirky unreliable computer management system.
the cars from 1981-1992 have a lot of single function electronics and miles of wires and tons of plastic connectors that are now very old and brittle which will make your driving experience like playing Russian roulette.
many of the cosmetic parts that you would need over time and parts to keep your car functioning may only be available second hand or aftermarket this means much of what makes the car operate will no longer be a GM part
parts from name brand suppliers like Eldebrock, MSD etc are great parts that are at least as reliable as the factory. but many people turn to discount auto parts Auto zone type stores that sell made in China cheap reproductions of the original once a car has enough of this garbage on it. you can no longer consider that car when comparing reliability and performance.
1993-1997 has a vastly improved Computerized management system improved power, yet today this is a old car with old electronics old wiring old connectors etc. scarce parts in some areas.
1998-2002 has a very sophisticated computerized management system
with available powerful engines that has a large supply of factory and aftermarket parts. yet it is a old car as well and can be tricky to find a clean one.
The key is on any of these cars is like I said start out with a low mileage one owner unmolested car that was well maintained with the service records to prove it. Good luck finding this unicorn.
if you want to see how hard it is to find factory parts for any particular year GM product, research the parts you think you would want factory parts for, then look it up at
http://www.gmpartsonline.net/chevy-parts.html
You will find many possibly needed parts discontinued, the older the car is the less parts they will have available.
As far as which is better? that would have to be a personal choice of what year make model car you fall in love with.
For me my favorite has always been the 1970-1978 Pontiac Trans am, Not because it is best, not because of Burt Reynolds but because I like the looks and it fits me at 6'3" like a glove. Most importantly you can get them with a Pontiac made engine not just a GM Or Chevy engine.
Yet if I went out to buy one today as a rolling project I would know when my project was done it would most likely be a much different car that rolled off the showroom floor so many years ago mainly because of parts availability would force my hand to change things to aftermarket parts.
while aftermarket parts are not the end of the world some are desirable especially the go fast parts. yet the aftermarket industry will always leave you needing more parts than they are willing to reproduce.
Its kind of like going to the Home Depot for a simple project that requires 30 separate items to start and complete the project, you will likely find 80 percent of what you need and want, the other 20 percent of items you will have to be creative and patient trying to locate.
So my advice to you is, if you have chosen Pontiac as your next car either a daily driver or a weekend cruiser, Make it one you love, make it one that you do not care what others think about it. the car is for you, the experience is yours. who cares what your friends say.
Be patient enough to walk away from a thousand cars that have titles in their sales listing that reads Mint condition. ( because people lie or are as blind as bats when it comes time to sell their car )
If this car is going to be a daily driver, and you plan on driving it like a daily driver. make sure whatever you end up with, can compete with modern cars of today, when it comes to braking.
a 1972 Pontiac Firebird in stock form cannot compete with even a newer Hyundai when it comes to 60MPH to 0MPH
So all your efforts will be for nothing if a modern car in front of you successfully completes a panic stop while your only a few feet away from their rear bumper.
I hope this is helpful
