Today I did some work underneath my 88 GTA 88.
I noticed that there ist much space between the floor and the cat and exhaust.
The reason Im asking is that I have Alston subframe connectors that Ill let a body-shop weld in. Will they fit? It will be tight but should be able to adjust the cat/exhaust slightly? I have a 3" magnaflow ctback, but the cat and y-pipe are stock. Has anyone done this install on a single-cat 88, could You tell me if it was an easy install or took some fabrication? The stock cat for this year/model looks longer than on most single-cat thirdgens?

It should clear and I have the dual cats. I had mine installed by a qualified Muffler shop and it did require a small bit of hammering to the hump in the floor over the cat. A good shop will have all the tools required to make adjustments. The passenger side front bar has a bend in it to clear the cat.

Ok, sounds good, thanks

Ed, are you saying that the floor pan has to be adjusted to make the Alston's fit?

When I said the floor pan has to be adjusted, IT"S NOT taking a sledge hammer to it. There were a few SMALL areas where the bar was very close to the floor pan and to make sure there were no rattles AFTER it was welded up, a hammer was used to give it some more clearance. The floor hump is already there, so when sitting inside the passenger floor area, you couldn't tell the difference in a million years.
Also the first photo of the Best 3rd Gen Wheel shows my R.S. front wheel with a portion of the front fender. If you look UNDER the back portion of the wheelwell, you'll notice a Silver pipe. That's the exhaust pipe that runs into the dual cats. I painted it Silver instead of having a dull steel finish.