Bollocks !! How can cutting a spring increase its rate ?

All you have done is to reduce its height (both free & installed), the rate will remain the same unless somebody heat treats it.

Most guys, lower their car by too much. Most do it for looks, not necessarily to improve the handling.

Take a leaf out of the car manufacturer's books & lower it by say just 1-inch, but increase the spring rate at the same time. This is why an HZ RTS car in stock form handles so well. Even the HZ GTS, one of Holden's best handling cars of the era, wasn't dropped on its guts.

The big trick is get the increased spring rate matched to the shock absorber's damping rate. It's almost a 'black art', look at how much time the V8 Supercar teams spend to get that extra 1% over the opposition, simply by altering spring & shock rates.

I doubt any insurance company would lose any sleep over a car which had cut springs, unless it was lowered to a ridiculously (illegally) low ride height. It would then qualify for a defect anyway.

Dr Terry