Grinding lowering springs
 

So after putting on the summer wheels with the track tyres I've been hearing a clunk at the front left wheel when turning left and going over bumps at low speeds. Today I've finally decided to investigate and found something concerning regarding the spring (Eibach pro kit) , pics attached. It literally looks like it grinded itself out at the top. What could be causing this? Should I urgently change out the springs?

https://i.ibb.co/0MgwGKq/IMG-20210717-202248.jpg
https://i.ibb.co/jL5rW05/IMG-20210717-202235.jpg

Grinding lowering springs
 

I haven’t seen 86 Eibach’s, but I’ve had them in a few other cars. From memory there is always a flat section like that.

It's supposed to look like it's eating itself out? I'm not quite sure this is normal.

No one here with lowering springs on stock dampers?

I'm on the Eibach kit with stock struts. No clunking or grinding issues.

It's hard to see what is really going on in your pics, but I wouldn't say you need to rush out and replace the springs quite yet.

This clunk could be a couple of things. Clunking can be a symptom of a loose tophat nut, try re-torquing that to ensure it is fully tight.

Spring ends may not be positioned properly and causing a bit of "spring bind". This thread is specific to TRD springs, but the installation requirements would be similar. https://www.ft86club.com/forums/showthread.php?t=116218

Did you install yourself or did a shop do it? If a shop did it, I suggest you bring it back to them for an opinion.

The car came with the springs already installed. The funny thing is the clunk wasn't there when i ran winter tyres, it only started making itself noticed after i put on the track tyres, I reckon due to the stiffer sidewall.

I checked the top hat and it seems it's tightened properly.

How do i check if the spring ends have been incorrectly positioned?

Realistically I think you would need to take the strut out and tophat off to see where it is positioned. I didn't install my own springs so unfortunately I can't help much more than that.

The other possibility is that your top-hat bearing is starting to bind / fail. That can also cause clunking. There is usually no visual indication when this bearing goes, you just start to hear it.

The stock tophat bearings are fine for stock springs but you get some different forces going through them once you lower the car or increase camber which can cause binding and early failure. If this turns out to be your issue, the best non-OEM replacement right now is the Group-N, or if you want a bit more camber/caster then the Pedders mounts are the way to go.

Hope that helps you narrow it down.