Bad idea...
When you cut the springs, you create different spring rates at all corners. Besides handling like a skateboard with square wheels, it's dangerous.
Save up a litte $$, and get proper springs. Roush springs are cheap, and the How to will show you how to do it yourself. You'll have to take them off to cut them, so just blow a few $$ and get better springs, and do it right.
Please don't cut the springs!
