Background:
Most of the aftermarket suspension kits available for MkIV Volkswagens tend to lower the ride height considerably. While these kits may look sporty, they rarely yield optimal performance and can be impractical or uncomfortable on rough and/or snowy roads.
As with any modification to your car's suspension, care should be taken to properly train yourself with the new mods on a closed-course race track. These mods can dramatically change the handling of your car and may surprise you in an emergency situation if you don't have the proper experience.
Why did I make this list? I was inspired by a recent question to collect data on some popular performance suspension spring offerings that do not alter ride height by more than an inch or so. Please limit discussions to kits with minimal lowering and help expand this list by supplying the following:
# spring manufacturer and model
# advertised spring rate
# tested or estimated working spring rate (this may be different than the advertised or "marketing" rate)
# estimated ride height change (depends on vehicle model options and weight distribution)
# cost
# recommended or compatible dampers
# additional info such as linear/progressive/coilover, etc
# website
An aftermarket spring kit:
OEM sport springs:
# published rates: OEM sport is 7% stiffer than non-sport
# estimated rates: 110-175 lb/inch depending on color code
# ride height varies up to 1" depending on vehicle options. (Limited edition models such as 337/20AE/GLI and "dealer-installed" springs offered in the VW driver-gear catalogs tend to be much lower, but not much stiffer than oem sport) In general, all VR6 cars have the sport aka "heavy duty" suspension. Most cars with OEM 17" wheels also have the sport suspension as part of the sport package. Few cars with 16" or 15" wheels (at least in the USA) have the OEM sport suspension.
# $200-$350 from VW parts dealer or $50 for a used set
# dampers: OEM replacement (Sachs/Boge/Monroe, etc.), Bilstein HD, Bilstein Sport, Bilstein TC, Koni Yellow, Koni Red, KYB AGX, Koni FSD
# linear spring
Neuspeed Sofsport springs:
# published rates: 220lb/inch front, 160 lb/inch rear
# tested rates: 140-230lb/inch front (depends on load and installed weight) Working rate on front springs is somewhere around 185lb/inch for 1.8T and closer to 200lbs/inch on VR6). According to Neuspeed, the VR6 and 1.8T springs are identical even though the model numbers on the website are different. These springs ought to perform better on the heavier VR6 models because the extra motor weight closes up the dead coils - thus raising the effective spring rate.
# -0.5" to -1.25" (both front and rear are lowered - rear lowered more than front on 2.0 Jetta - lowering is more even on VR6 GTI)
# $165-$250
# dampers: Bilstein HD, Bilstein Sport, Bilstein TC, Koni Yellow, Koni Red, KYB AGX
# mostly linear spring with progressive dead coils (progressive ramp up of spring rate depends on vehicle weight)
#
http://www.neuspeed.com H&R OE Sport springs:
# published rates: ~15% stiffer than OEM sport
# tested rates: 130-230lb/inch front (depends on load and installed weight - front working rate around 210lb/inch)
# -0.5" to -1.25" (front is lowered more than rear - more lowering than advertised on heavier Jetta and VR6 models)
# $175-$250
# dampers: Bilstein HD, Bilstein Sport, Bilstein TC, Koni Yellow, Koni Red, KYB AGX
# mostly linear spring with progressive dead coils (progressive ramp up of spring rate depends on vehicle weight) For lighter cars such as 1.8T/2.0, ramp up slope should be slightly higher than Sofsport resulting in a stiffer feeling spring.
#
http://www.hrsprings.com Shine SRS springs:
# published rates: 225lb/inch front, 180lb/inch rear (1.8T), 250lbs/inch front, 200lbs/inch rear (VR6)
# tested rates: 250-280 lb/inch front, 160-200 lb/inch rear (depends on engine and comfort preferences specified. Working rate for front springs is around 250lb/inch)
# -0.5" to +0.25" (rear is lowered, while front is static or raised very slightly depending on vehicle weight & options)
# $239
# dampers: Bilstein HD, Bilstein Sport, Koni Yellow
# linear springs
#
http://www.srsvw.com H&R "dunebuggy" coilovers: (no longer available???)
# published rates: 400 lb/inch front, 285 lb/inch rear
# measured rates: front=400, rear=170 - can be swapped for other standard sized coil-over springs.
# -1.0" to +1.0" (continuously adjustable for raising or lowering and corner-balancing)
# $1000-$1480
# dampers: integrated into coilover system
# adjustable height coilover with progressive-rate springs
#
http://www.hrsprings.com Ground Control coilover conversion kit:
# published rates: 250-525 lbs/inch (exact spring rates catered to your specifications)
# tested rates: within 1-2% of published rate
# free length and ride height catered to your specifications, continuously adjustable for up to 1.0" in ride height change or for corner-balancing
# $419/kit
# dampers: re-uses OEM style, Koni or Bilstein
# custom Eibach linear-rate springs with height adjusters adapters for your existing dampers
#
http://www.ground-control-stor...CA=65
Notes on Dampers (shocks/struts)
# High-pressure gas dampers such as Bilstein HD tend to lift the car when compared to other dampers. The amount of lift depends on the weight of the car and the springs installed, but in most cases, it will be 1/4" to 1/2". This gives a little more flexibility in choosing a suspension and ride height because if you want to be higher, you can get high-pressure gas dampers. If you want to be lower, get low-pressure dampers.
# Many folks believe Koni is more comfortable than Bilstein. Bilstein has a sport/touring feel (perhaps like a BMW M3?) while Koni has a more sport/luxury feel (perhaps like a Mercedes/AMG?) You'll have to decide which is best for you.
# OEM dampers can be modified for higher performance via custom valving and re-filling with different viscosity damper oil. This kind of work needs to be done by a damper specialist with the proper machining and testing equipment. Unless you have good connections, you may end up paying almost as much as the cost of a brand-new off-the-shelf damper for this service.
