I did coils on my 91 GTP and found the 250s were to soft I’d also recommend 300.
You can use the rear sway bar out of a 97 montecarlo if you can find one. It’s the largest stock bar there is. 95-96 might also have these as well.
I have a powder coated strut tower bar from a 96’ cutty vert. In my 91 it rubbed ever so annoyingly on the EGR so I took it off. I’ve posted it on eBay here and there but did not sell. If you’re interested I’d sell it on for a low price but couldn’t say what shipping would be or if it would rub your EGR as well. It’s more likely to as they’re both 1st gen GPS?