Linear springs are smoother in response than the standard springs.  They are wound from smaller diameter wire and have less coils.  This allows for the spring to have a more linear response through the suspension stroke.  The front end tends to have a more constant response instead of getting more aggressive as the car rolls deeper; which is the case with the standard type springs.  The Pink Springs are similar in rate to the Medium, Blue Silver Springs, (part no RX28A-11).