I run 555s on my G body Cutlass and drive it daily. I Auto crossed them for a couple years but now have Falkens I swap out for that. For a street and occasional auotX I like the 555s as they perform pretty decent in all situations. The first set were worn out in a year with only a couple race events on them. But I drove fairly aggressively on the street, lots of curvy roads on the way to work. The second set I babied and they had only a little wear after about 6 months. While my car is down for a motor swap my teenage son borrowed my wheels and tires for his Cutlass. They were near bald in 3 months

of his style of street driving. That should give you an idea on driving style and wear longevity. The tires handle well and are plenty responsive and comfortable on the street. Only thing I don't like is they get a little slippery in the rain, but I am lucky to live in the southwest desert and don't see too much of that.
While you're shopping around check out Speedtech's suspension packages too. I had a similar suspension as you mentioned as my first "get my feet wet" set up and eventually felt like it was limited. As I've gotten more serious about improving handling (much like going fast down the 1/4, it's hard not to want more once you get a feel for it) I've switched to a full Speedtech package on my Cutlass and the car now handles at a higher level. Speedtech suspension is simply straight forward, void of gimmicks, high quality parts that work; and are a great price for the level of quality you get. All parts are backed by a support group of folks that are heavily involved in building, driving and racing these cars and are ready to help you get your car set up.
Another cool thing you might like about the Speedtech suspension is the rear sway bar is adjustable. If you go with the rear coilover conversion like I did you can properly dial in shocks
and you have 3 options for lower rear control arm mounting position to tune your launch. In less than an hour you can take a car set up for cornering and set it up to go drag racing too. Coming from a drag race background I still enjoy hitting a test and tune night now and again and these options for tuning are nice to have.
Take a peek
HERE to see if these parts fit your needs.
Good luck with the build, you'll really enjoy being able to turn and stop as well as go straight fast!