QA1 GD510-10700 Front Pro Coil Shock System, 99-06 Silverado 2WD, Double Adjust Product Overview Upgrade the front suspension of your NBS truck with QA1’s coil-over conversion. Designed for 2WD 1999–2006 Silverado and Sierra 1500s with QA1 tubular upper and lower control arms and includes QA1’s double adjustable coil-overs. DIAL IN THE PERFECT STANCE QA1’s front coil-overs give you 1" to 3" of ride height adjustability right out of the box. Want to go lower? Pair them with QA1’s 2" drop spindles (Part Number: 9056-120) for a total drop range of 3" to 5" up front. Whether you're aiming for a subtle level or a slammed street look, this setup lets you get it just right.