Lucid, I forgot to mention i have Brembo 6pot BBK and a set of Yokohama A048 R compound tires installed for my 2nd trackday. But the brakes might be one of the reasons why my car is unbalanced.
I noticed I get more more oversteer when the rear seats are removed. You might want to adjust the front suspension a bit harder if that happens.
If you really want weight saving (which im currently planning to do), I suggest swap the front seats with some light weight bucket seats and change the stock exhaust to some titanium exhausts. In that case you are just taking weight out from the center of the car instead of messing with the balance. Have fun on the track