tire question

[84LX89GT]

I have both wheels, turbines and ponies. The turbines were on GT's from '87 to '90 and in '91 they switched to the Pony wheels as stated.

I have 245/50/15's right now on my GT (on the back) BFGoodrich Euro T/A's and they're good handling, OK traction tires. I wanted to get a wider tire with a larger contact patch and they work pretty well for that. On the Pony wheels (came with my GT) it had some Z speed rated 225/50R16 tires Bridgestone RE940 and those tires were unbearably stiff, the car wandered everywhere, caught every groove and had horrible bumpsteer as well as reduced ground clearance. You can really feel the flaws in the stock suspension with those tires.

If you get wider tires, you'll have to run slightly lower air pressure to maintain a good contact patch because as tires get wider on skinnier rims they tend to balloon out not only on the outsides, but also in the middle of the tread area. As a result the wheels can tend to shift on the tires a bit, but not very noticably.

the next time i get tires, i'm just going to get some quality stock size tires with a higher speed rating (higher speed rating tires have stiffer sidewalls and subsequently handle better) and relatively decent treadwear rating. You can get lower profile tires with an aspect ratio of like 50 or 55 but then they start riding rough and usually have a higher speed rating anyway because the shortness of the sidewall strengthens it.

I personally like to get tires with a lower treadwear rating because they leave more rubber on the road to stop/grab traction with. I also like have a margin of error in case i enter a corner too fast and have to rely on the tires.

As far as load rating of the tire goes with a 3000 lb car you're not likely to exceed the rating of a reasonable size tire and probably won't cause enough stress on the tire to cause it to fail unless it's underinflated at high speeds.
This is just my opinion though, so only you can decide what you want for your car.