doubt they will get much better with lowering springs. Maybe try and get a set of stock springs cheap, and cut them to your desired drop. I know the sportlines i had on my 03 made that car ride like crap. I loved how low it sat, but it rode like shit all the time.
I have a set (4) BBK 1.5 drop springs.(pn 2501) New from Summit $ 179.99. Used from me $75.00 I bought them from my bubby who parted out a 89 hatchback but my car Is a convertible. (there Is a diffrence). Im In Westland If you are Intrested.
Buy stock ones and cut them.If I remember correctly, Fetterley and I cut mine 3/4 coil and got over an inch of drop and it rides great! A few buds put A/M lowering springs on their stang and swapped them out for cut stockers.:1syellow1