Suspension Lowing Kits, Lowering Springs, Lowering Coil Springs
Lowering springs can be a great way to increase the suspension on your vehicle. Suspension lowering springs are designed to lower the ride height for a lower center of gravity, faster turning, and overall suspension performance improvement. In addition, the lower stance gives your vehicle a MUCH nicer look, as it detracts from the "on stilts" look in favor of accenting the length and curves of your vehicle's body.
Choosing the right ride height for your vehicle's suspension:
How low should you go?
Each type of lowering spring is designed to give your vehicle a certain level of lowering that will affect drivability. Generally speaking the lower the spring, the nicer the look and suspension performance improvement, BUT, at the expense of drivability on anything other than flat roads. For that reason, most lowering springs for your car can be put into 3 categories.
OE Drop Springs: These types of lowering springs give a very marginal drop for your vehicle. Usually between 0.25 inches to 0.5 inches, these springs lower your vehicle the minimal amount possible. This gives a very marginal increase, with minimal impact on look and performance. These might be optimal if your car has a situation where you are already pretty low, but could use the extra quarter to half inch of drop. Such situations include having unusually large wheels and/or tires, having shocks that already lower your vehicle to a certain degree, or having an unusually low body kit installed.
They also are a good idea if you need to replace OE springs but don't want to pay exorbitant dealer prices for factory parts.
Examples: H&R OE Sport Springs
Standard Drop Springs: A lowering spring of this ride height is considered normal, dropping most vehicles about 1 inch to 1.5 inches depending on the exact car. This is the safe choice for your vehicle, as these types of springs it will give you enough of a drop to give you a suspension upgrade without being too low to drive around comfortably and without having to take speed bumps and driveways at an angle to avoid scraping. The difference in appearance is also noticeably better than your vehicle's stock ride height.
Examples: Eibach Pro-Kit Springs, H&R Sport Springs, Tein H. Tech Springs, Tanabe Sustec NF210, RSR Down Springs
Race Drop Springs: This type of spring offers the most aggressive drop possible. Springs in this category drop most vehicles anywhere from 1.75 inches to 2.5 inches, and for some vehicles, even up to 3 inches. This type of suspension set up is only recommended for the owners who want an extreme drop and super low center of gravity, but at the expense of an adverse daily drive. Approaching steep driveways and large speed bumps at an angle (aka angling) may be required in order to prevent scraping the bottom of your car. Additionally, a camber correction kit may be required if your tires are "butterflying" (showing positive camber as oppose to being perpendicular to the road).
Examples: Eibach Sport-Line Springs, H&R Race Springs, F Tein S. Tech Springs, Tanabe Sustec Gf210 and Df210 Springs, RSR Race Springs
Lowering Spring Brand Comparison:
H&R Springs vs Eibach vs Tein / Others
Eibach Lowering Springs: Eibach makes a very good spring. Managed by true performance enthusiasts, very well respected, and extremely well marketed, Eibach springs are perhaps the most popular springs available in North America. There are no problems in the quality department as they are a first class spring company, and unlike many springs, they are manufactured at top notch manufacturing facility in the United States.
Eibach springs are generally the more aggressive performance type of spring, geared at the car owners looking for performance over comfort. Eibach spring rates tend to be a bit stiffer, so they offer a more responsive turn, but they could be a little more rough on the buttocks on bumpy streets. Compared to most other springs though, the ride is still relatively good, even on the more aggressive Sportline drops.
Country of Origin: USA
H&R Lowering Springs: H&R is a world class suspension company. There should be no motorsport professional on Earth who has not heard of H&R. Produced in state of the art manufacturing facilities in Germany, H&R takes their suspension parts very seriously. Involved in most forms of professional racing, and the suspension company of choice by the world's top automakers racing programs (Mercedes, BMW, etc), H&R is perhaps the best suspension company on Earth.
Since they figure that career racers would prefer full coilover suspension setups, and that lowering springs are designed for people who may like performance but are more concerned with getting from point A to point B, H&R springs are designed primarily for a comfortable daily drive. Being a relatively soft spring, it handles bumpy roads much better than most other springs, but they lack the extra stiffness of springs like Eibach.
Country of Origin: Germany
Tein Springs and Other Spring Companies: Tein is a rather unique case when it comes to springs. Though they are not very popular in their original home country (Japan), they have nonetheless done a phenomenal marketing job in the U.S. giving them a high level of popularity. Unfortunately though, their strength lay in their low end (the BASIC line) of full coilover systems, not in their lowering springs. However, this has not stopped people from thinking that the quality of their low end coilover systems is matched in their lowering springs. Despite being a rather average spring in terms of performance and drive comfort, people still buy them.even though their price is often even HIGHER than better quality H&R and Eibach springs.
As for the other companies, they share similar qualities. Often they are they are produced as an afterthought of companies who are successful at another product (usually exhausts) and use their name to market average springs at high end prices. Oftentimes, they will outsource spring production to an outside company and not put the effort and R&D that companies like H&R and Eibach put into their springs. That is not to say that there are not some good springs out there, but they are far and few between and tend to be exorbitantly priced.
Countries of Origin: Japan (rarely), but more likely China, Taiwan, South East Asia