[dave33]

The difficulty with changing springs around is not only getting the right size and spring rates, but also the correct spring length.

I initially used springs originally intended for a Mitsi Evo in the front of my 33 for racing.
Time spent with calipers and measuring tape at a wreckers yard can pay off !

To get the lower ride height I wanted, I had to have the springs shortened. Not by just cutting them, but rather by having a spring making firm heat treat and properly re-set the length. I then had to send the shocks away to get them shortened otherwise the springs would fall out of their mounts if I went over a bump and unloaded the suspension.
(BTW if you put stiffer springs in standard length shocks, the car gets taller, not what you really want!)

Using other springs is do-able, but its not necessarily a quick/cheap fix. You also need to make sure that the spring rates you use are appropriate. (Go too stiff on the front, and you'll have AWFUL understeer come track day.) I got hold of the calculations for working outspring rate and worked out the wire diameter and number of coils needed to obtain the right poundage for front and rear.

For road use, the commercially made spring kits allow you to get the car a bit lower (and stiffer) using unmodified shocks. King springs or similar are likely to be right first time, and a lot less trouble...

Good luck !