Richard and I have been looking into lowering our cars but there really aren't any options out there that have been appealing to us, other than the Eibach springs. I was browsing Tein Japan and noticed they just posted a new item for the IS-F that wasn't shown on the Tein US website!
All the coils out there, more specifically, Tein and JIC have "compatable" coilovers. They are the same part as the IS350's hence the softer ride.
I called up Tein today and got some specs for the Comfort Flex. The valving and spring rates for the comfort flex are specifically engineered for the IS-F. 12kg/10kg vs the comfort sport (IS350) 7kg/7kg. This makes a big difference because we are much heavier overall especially the difference of load in our front because of our monster 5.0-liter.
They have them in stock right now on the west coast and are the same price as the comfort sports.
Just wanted to give you guys a heads up for another option or if anyone that already have these installed we would love to hear your input!

One of us might try these out soon and if its a good quality performing item we will be dealing with Tein in the near future!

 

I will be very interested in your feedback if either of you get these installed. I currently have Eibach springs and am happy with the ride height but would in coilovers for an improved ride quality.

 

I just checked the Tein Japan site and I'm under the impression that Comfort Flex will be better than Comfort Sport. It has independent shock body adjustment and seems like the kit comes with upper mount for the rear unlike the CS.

For me personally, I had a bad experience with the Tein Comfort Sport on my IS350. One of the shocks started leaking a month after the warranty expired. It took quite a while to get it fixed by Tein.

I have JIC on my F right now. I thought Tein CS's ride quality was good until got the JIC. The ride quality is firm but it's very compliant. Even when it's set to the stiffest setting, I don't get the stiff rebound on uneven surfaces.

Hopefully, Flex is built better. Just from the specs, it looks good. Good luck and give us a review after you get it.

Terrance

 

it not about how its built its the valving and spring rates they use. you cant compare a cs with a flex. There is NO comparison. Flex are teins flagship shock besides the upper models that are for race use only. I feel that the FLEX will be a awesome shock. Fall back is no independent bump and rebound settings. I am interested in seeing the new flex setup.

 

the thing is is that the tein cs is not made for the IS-F. it's made for the is250/350. JIC's are the same way and I am almost positive about that. The comfort flex is made SPECIFICALLY for the IS-F.

 

cant wait to see pics of this. i am currently contemplating coils for my F, and am constantly researching which brand to go with. ive heard many great reviews about tein, so im hoping this version will really enhance the ride of the F.

 

I like how this is sounding!

 

whats the status with comfort flex coilovers?

 

The only thing that needs to be made "specifically for the IS-F" is the valving and spring rates. There's absolutely no reason to change anything else - the coilover assembly will fit both cars and work great on each if the valving and spring rates are correct. JIC makes a set valved with springs specifically for the IS-F, and a different product (based off the same coilover shock assembly) with valving and spring rates for the IS-F.

Javier

 

Hmm...sorry to hear I have had MY tein CS and they are pretty sic ride at lowerest setting on thread and have stiffness at half setting been super smooth ride on trac drifting etc..can even roll through Austin Tx and OK without issues packed with five people! if the FLEX is bette rI cant imagine that would be awesome

 

I'm updating this thread with more recent info from the Tein site. Javier is correct, and it turns out these are indeed also part of the Comfort Sport line, just valved differently with different spring rates for the IS-F.

http://www.tein.com/price/lexus.html

LEXUS IS F
USE20L 08+ CST
Part Number GSC72-KUSS3
$1700.00
F 12/671
R 10/559

For comparison:
LEXUS IS350
GSE21L 06+ CST
Part Number GSL90-K1SS3
$1700.00
F 7/392
R 7/392

 

I have them on my F and I love them.

 

Hey Javier,
I agree with you understand what you mean.
I didn't know that JIC made coilovers (specific valving/spring rates) for the IS-F. They don't have anything listed or marketed for the IS-F on their website and I have not tried to contact them directly.
I am guessing you had? JIC makes an awesome product and I was glad enough to own a set of FLT-A2's for my IS300 but in this case I would be hesitant to purchase JIC's for my IS-F w/o appropriate info or testing.

I am not saying that JIC does this but I am sure some manufacturers just throw on a different set of springs on a compatible shock assy. and say its made specifically for ones car. In all honesty we really wouldn't know w/o in depth testing.

 

^^ Kerry, I personally know the IS-F that was used by JIC to R&D the coils for the IS-F....

There must be at least 50 IS-F owners running JIC coils made speficially for the IS-F..

I just think its a lack of website updating..

But if you call in, you can get the IS-F coil part number.

We had the 1st set made for a SEMA IS-F, back in 2008.

Joe Z

 

awesome info!
Thanks for the clarification Joe!