Originally Posted by ISF08

I have since left my ISF in the rear view mirror and gone to the dark side that is BMW. In all seriousness, I switched to a sport F30 and the difference is incredible. The ISF did everything so well, but the suspension was just done so, so wrong. Even after test driving a 2013, it was not that much improved, if at all. You CAN have comfortable in the streets and excellent at the track. I know because my F30 is proof. I don't know what Lexus was thinking when they designed the suspension for the ISF but it really is a shame because I love the car. Stiff does not equal performance. If BMW can design a car that corners like its on rails but yet can traverse a broken road without destroying your kidneys, so can Lexus. The reason why I chose not to go down the rabbit hole that is aftermarket suspension is because every car has a large amount of time and money put into it with engineers that design the suspension to a specific spec. Changing that changes the entire geometry of the car, and I would rather not have to deal with that. I also looked at the GSF, and it is nice, and much improved ride quality, however it felt "cheap". By that I mean the ISF felt like it had better quality materials than the GSF, with the F30 beating both. My personal opinion would be this: if you want a smoother riding car, get rid of the ISF. It is just not the nature of that car. Of course, when my warranty is up (7 years/100k miles), I will be getting rid of the BMW as it will be a money pit.

Originally Posted by Vitveet

Not to rain in any parades or anything but something is SERIOUSLY wrong if you didn't notice a difference between the '08 F and '13 Fs ride comfort....it's literally night and day performance wise along with comfort wise! Results were proven in the lightning lap as well.
Also, to think that the GSFs interior is "cheap" compared to the '08 ISFs....soooooo far off. Ask 100 people and I'm quite sure you'll be the only one, maybe one other, with those opinions.

V.

Originally Posted by FIGS

Its hard to say because like all manufacturing processes it depends on the assembly line that they are on. All of our BC coilovers go through the custom build queue which means that are assembled in FL from custom valved shock bodies. BC NA will start to offer individual dyno tuning shortly as they are setting up a new facility at the moment for race support. It will cost a little more to run them through this process but if consistency is a concern it will be available. Its also hard to generalize since many people have purchased these from other vendors with the incorrect spring rates or valving or they did not take the time to work through tuning the dampers and used them as it out of the box. We put a lot of effort into support our sales with setup and installation advice, phone support etc. Most ride harshness is related to improperly configured shocks (overdamped). Most vendors would rather violate the MAP policy and defer to BC for support when its needed.

To BC's credit they have worked through the small issues over the years and the current product is better than ever, but its also not as sophisticated a valving as the KW. That being said we have a large instance of customers looking to respring their KW because they bottom with their current setup. The KW setup is undersprung because they only take into account the factory vehicle with no mods. We can offer a custom sprung KW setup or upgrade a KW setup with swift springs, but at that point you are in the same range as the Ohlins RT setup which we feel is a better implementation (full upper hat shock replacement vs reusing the rear factory hat.)

The last variable I will mention is that of the rear bushings, because the can impact the shock efficiency. The staked factory rubber bushing acts as an undamped spring and restricts the shock stroke adding a delay in the damping effect. Our rear LCA replaces the inner bushing with a spherical which nets a more instant location of the arm over the shock cycle. This means more dig traction and overall the shock works better to damp the smaller high speed events. We are able to get more out of the lower cost solution because we are reducing the load on the internal damping and allowing the linear spring to do more work. With each solution there is a compromise.

Mike