Lowering Capabilities – A standard kit will allow for a ride height adjustment of stock to a 3″ drop (varies per application). By replacing the shock insert(s) with sorter units (1″ to 2″ shorter) the height adjustment will then be 1″ or 2″ drop all the way to a 4″ or 5″ drop (depending on the application).
We don’t have a global adjustment that works on every kit so each kit gets personal time to determine what needs to change in order to best suit the setup. Great example would be a standard 350z setup has an adjustment of stock to 4″ drop up front however the rear has only adjustment from stock to 3″ drop. By selecting an Extreme Drop setup we leave the fronts alone (other than if you selected another spring rate) as they have plenty of adjustment however in the rear we will replace the springs with ones that are 30mm shorter than standard and an 1″ shorter shock insert. By doing this the entire kit now has an adjustment range up to a 4″ drop.
Spring Heights – Normally in an independently adjustable coilover spring heights don’t do much as your adjusting your ride height as much as possible off the bottom adjustment (this keeps you from loosing shock travel). However, cars with McPherson type struts (generally only found on the front of the car) will have a unique issue with a really low ride height. At a certain point the spring or spring collars used to hold the spring up will sit behind the wheel/tire instead of above it as the factory suspension was setup. This limits the cars backspacing capabilities which in normal terms just means how far a wheel can sit under the car. When using some aggressive/wide wheel setups you may need this extra room that the spring and/or spring collars are taking up. By using the same spring rate selected but running a 20 to 40mm shorter spring it will allow you to adjust the spring back up the shock (the difference they are shorter) thus giving you back the same clearance as stock and still being able to run the ride height desired.