Hi,
Had the above fitted a few days back so I thought I'd let folks know what I think.
They do make a big difference, the steering feels much more responsive now making the car feel more agile and much more engaging to drive. Dare I say it, its more fun now. Obviously the E89 is never going to set the world on fire in the steering stakes but everything feels much improved and for BMW EPS its not too bad at all now, at least as good as the EPS on my E85 if not better. Some of this will be that the camber pins have also been removed and the camber maxxed out which improves turn in on its own. Overall its a major improvement, makes the car feel more akin to a sports car with a responsiveness that wasn't there before. The "slop" in the steering has gone and no real sense of the "just off centre dead spot" particularly at speed, the detachness you feel from the front wheels has greatly deminished. Honestly its how I would have liked it have come from the factory. I can see why E9x 3series owners rave about this mod, particuarly when you consider that the factory intended the compliant fluid filled bushes in the original arms to be coupled to runflats with no give. With a lot of owners ditching the RFT's in favour of tyres with softer sidewalls your effectively adding even more slop into the system.
However, like most most things in life there is a price to be paid. Theres an increase in the NVH, in terms of general road noise there's probably no real difference, but you do hear and feel it over a bump. Its kind of like I've taken off my non runflats and replaced with RFT, but not as extreme as that. Fortunately though there's no real sense of bump/torque steer, not like the E85.
In summary I can see BMW's logic here in fitting the arms they did at the factory, as at the time they were aiming for a BMW SLK. Something alot softer than the E85 with mass market appeal which of course the E89 is. However I do believe that if the M divsion had built an E89 Z4M or even a M LITE (lets call it an E89 Z4 M35IS
) the first thing they would have changed would have been the control arms and ditched the runflats, just like they did on E9x M3. Next up would have been the suspension and then the sway bars/ARB's. They would have left the engine/box alone as they were deployed in some M cars anyway. As I've already got the B12 kit, which made a huge difference its ARB's next for me when I can find someone with actual stock! 
Think it might be time to sell the E85 and just keep the E89!
Had the above fitted a few days back so I thought I'd let folks know what I think.
They do make a big difference, the steering feels much more responsive now making the car feel more agile and much more engaging to drive. Dare I say it, its more fun now. Obviously the E89 is never going to set the world on fire in the steering stakes but everything feels much improved and for BMW EPS its not too bad at all now, at least as good as the EPS on my E85 if not better. Some of this will be that the camber pins have also been removed and the camber maxxed out which improves turn in on its own. Overall its a major improvement, makes the car feel more akin to a sports car with a responsiveness that wasn't there before. The "slop" in the steering has gone and no real sense of the "just off centre dead spot" particularly at speed, the detachness you feel from the front wheels has greatly deminished. Honestly its how I would have liked it have come from the factory. I can see why E9x 3series owners rave about this mod, particuarly when you consider that the factory intended the compliant fluid filled bushes in the original arms to be coupled to runflats with no give. With a lot of owners ditching the RFT's in favour of tyres with softer sidewalls your effectively adding even more slop into the system.
However, like most most things in life there is a price to be paid. Theres an increase in the NVH, in terms of general road noise there's probably no real difference, but you do hear and feel it over a bump. Its kind of like I've taken off my non runflats and replaced with RFT, but not as extreme as that. Fortunately though there's no real sense of bump/torque steer, not like the E85.
In summary I can see BMW's logic here in fitting the arms they did at the factory, as at the time they were aiming for a BMW SLK. Something alot softer than the E85 with mass market appeal which of course the E89 is. However I do believe that if the M divsion had built an E89 Z4M or even a M LITE (lets call it an E89 Z4 M35IS
) the first thing they would have changed would have been the control arms and ditched the runflats, just like they did on E9x M3. Next up would have been the suspension and then the sway bars/ARB's. They would have left the engine/box alone as they were deployed in some M cars anyway. As I've already got the B12 kit, which made a huge difference its ARB's next for me when I can find someone with actual stock! Think it might be time to sell the E85 and just keep the E89!
San Francisco, CA
