Alright so I have an extra set of these incredible springs up for sale! Yes, I still have the ones on my 07 STI (they arn't going anywhere ), these are an extra set and are brand new in a never opend box. I was going to open them to show you a comparison of my stock STI springs and these, but you can probably imagine a set of orangey red springs with like 2 extra coils in them.
front: 5.8kg/mmn (324lb/in)
rear: 4.4kg/mm (246lb/in)
The GF210 coil spring is geared towards maximum performance, without compromising daily driveability. A subtle drop provides an aggressive stance, while the higher spring rates (+20% - 30% over stock) provide excellent handling and vehicle stability characteristics. These springs provide a very noticeable gain in performance when installed.
The GF210 is well mated with a performance shock upgrade to extract the full potential of the coil spring, but will also work with factory equipment.
Each coil spring application is tested for fitment and optimal weight distribution for sportier handling.
Looking at the spring rates they are obviously pretty stiff, but they actually ride very smooth on the open road. This is because of the spring's progressive dampening. If you hit a quick jarring bump, the spring takes it similar to the stock STI springs, yet once you take your first on-ramp you will find much more available grip. Turn in response is much tighter which I find makes hitting the apex of a turn much easier. The body roll is brought down to a minimum which also makes the car much more stable when taking a turn at high speeds. The drop is just enough to give the car a more aggressive look while not looking to "slammed." Tanabe offers a few different springs, one is for looks and these are for all out performance. What better to put on an STI?
Just an FYI- Tanabe makes these springs for the 05-07 STI (not sure about 08 fitment). For the 04 STI, there is another spring with a different part number. Both sets of Tanabe springs will work with any USDM 04-07 STI, but the ones specially made for the MY04 have slightly softer spring rates. I guess it all boils down to what you're personal preferences are, but I cannot imagine why they have softer springs for the 04
Also, according to a vendor these springs will also work on a GC8 and 02-03 WRX; 04+ tophats are required.
The MSRP on these springs are around $280+ shipping, I'm willing to sell these for the same great price I sourced them for which is $210+ shipping or best offer. Please PM me or send me an email at firstname.lastname@example.org.