Bhai waisay zarori nahi ha.. 
Mainay apni gari k front springs change kiye thay stock springs me shayad 2 coils bhi zyada thay aur unn ki uncompressed ki height bhi zyada thi lekin unn se gari neechi rehti thi jo aftermarket purchase kiye thay unn ki height to kafi kum thi lekin jab gari me install karway to gari front se bohat unchi ho gai thi aur ride stiff bhi... 
Phir wapis stock lagway...
So i guess spring rate pe bhi depend karta ha kuch chotay springs bhi hard ho saktay hain aur kuch lambay walay soft bhi ho saktay hain.. Sara game spring rate ka ha.