I did a search and nothing really came up. Now I have been hearing some mix answers but does stainless steel brake line improve performance or do nothing at all? Thank you.

 

They improve brake feel. You won't actually stop quicker.

 

I recently got a SS brake line on my Z and I really can't tell the difference that much.

The funny thing is that with SS brake line, brake pedal feel little firmer initially but as you press on the brakes pedal more, it feel little more mushy.

I don't think I have a leak because I check all 4 line.

 

If it gets more mushy the longer you brake, then you have air in the lines. You don't necessarily need to have a LEAK. But air is still in them from when you changed them. I would bleed them again.

SS lines won't help you stop faster, they are to improve pedal feel and response. And in most cases(street driving) you won't notice any diffrence at all. The diffrence comes when you track. When the brake fluid gets really hot, SS lines won't expand like stock ones will. And thats what helps keep stiff pedal response after long track use.