There are many factors to consider when choosing the right coilover system for your car. Some have advantages that may fit into what you're doing with your car so on with some info
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KW is a great suspension company and is the one of the goto highend coilover company. Their Variant line offers many advantages over others. Stainless casing is great for people that are subject to all weather conditions. Twintube design and the patented dual adjustment damping. But these points also offer some disadvantages. Stainless steel dissipates heat much slower which can lead to fade and aeration, which can hurt overall performance. Twintube is low pressure design, which allows for softer ride but is more prone to aeration. Twintube construction does not allow for inverted mounting, thus doesn't offer inverted setup for mcpherson type suspension.
Stance suspension mainly offers monotube coilovers for its many advantages. It allows for larger diameter piston and high pressure, which can react much faster to smallest movement, no dead spot. Since its single casing, oil can dissipate heat faster, less fade. Oil and gas are separated so it can be mounted inverted. There are clear advantages to the inverted design. That's why most high end cars come with inverted monotube from factory and most race cars use monotube design.
Here is a simple simulation showing the actual forces applied on both designs.
This test was done to simulate a 3200lbs car cornering at 2G's with no weight transfer. Force applied was 1600lbs. Results show that inverted design is 300% stiffer. Less deflection means less stress, less wear on the seals, less friction.
Left to right, Stance,Borchuan,KW.
Ride quality can be subjective and can be its own topic. Engineers at Stance have been building monotube suspension since 90's and developed a right balance of performance and ride quality. Key is digressive valving with good low speed damping, which gives it sporty yet non fatiguing ride.
Stance suspension has partnered with Cyber Evo team in late 2011 and is the current suspension of choice for the Cyber Evo. Big testament since Cyber team is not the one to settle for less. You can find more info on
www.stance-usa.com
The Super Sport Coilovers are finally instock after many testings, revisions. It comes with adjustable camber plates,inverted dampers,adjustable sway bar endlinks.