[bobcowan]

Unless the suspension is set up for it (like a drag car) front end lift is generally caused by a shift in CG to the rear, and compression of the rear suspension. Fortunatly, that's a cheap and easy thing to test for.

Jack the car up in the back, and put a cable tie around each shock shaft. Put them very close to the shock body. Go drive the car around as you normall would for about 5-10 minutes. Take a look at the cable ties, and see where they're at.

Now do a couple of hard launches that causes the front end to lift. Take another look at the cable ties, and see how much suspension compression you're getting.

If it's a lot - or if the shock gets completly compressed - move to a higher spring rate. Or increase the shock compression rate if possible. Changing springs is the the best choice. But adjusting the shock is free and easy. You can always change the springs later.