too much understeer now!

Jessobear

Try driving the car with the VDC on and off and see if it makes a difference.

But probably your biggest issue is simply that you have too much rear tire. You've actually increased the front track relative to the rear, which should reduce understeer. You could play with raising the front tire pressure relative to the rear pressure. Sounds like what you're doing currently is the opposite of what you're supposed to do:

Tire Tech Information - Air Pressure for Competition Tires

Also, take a look at your springs and see if you can't figure out their rates. Eibach often prints them on there. You should also be able to tell if they're progressively wound by looking at them. Progressive springs will have a non-uniform winding. There's a chance that the front spring rates were increased relative to the rear rates, which would increase understeer.