I believe in stock springs since they have the proper spring rate to support the
weight of my car. After careful measuring of the suspension, I alter the stock
springs to get the proper ride height. There may be nothing wrong with unscrewing
the gland nut, sliding on the coilover sleeves, and screwing the gland nut back on.
Some people have good luck with Ground Control as a sleeve brand.

Harder springs are not needed unless a car is coming down
from being airborn and you don't want it bottoming out or unless a car is on a banked
track with forces pushing the car downward.

I don't yet understand what softer springs do for a car, but I'm willing to listen.

For a more solid suspension, I would use poly graphite bushings. I don't recall
the company name at this moment.
I would use bigger diameter anti-sway bars than what came on the car stock,
.............but I like a car that will corner flatter than most.

The way I find things that will interchange is to go to LKQ and for $2 I get
all day admission and a parts interchange printed out. You might carry in an
old suspension part and see if it will fit onto the junkyard car
I sometimes will spend the day measuring, but everything I measure goes
into a tech folder for future reference.

I may not be a suspension guru, but you can read some of my suspension
articles by clicking the link to my shop forum in my sig.