To anybody who has installed Powerflex Bushings and Bilstien's on their E39 540

[dsneal]

I have an '01 540iA with sport package. 153k miles. It is truly a wonderful car that has been well-maintained and never tracked and won't be. It is time to do a suspension refresh and I want to firm it up a bit, but don't want it to ride like a race car. I have consulted with the folks at Bav Auto and ordered Powerflex urethane bushings and new control arms with Powerflex Urethane bushings installed. The sway bar bushings are Powerflex Purple and the rest are Black. I also ordered Bilstein Sports and the related rubber parts that go with them. The packaging on the Powerflex Black bushings say that they are "race ready." I have ridden in an E39 M5 and loved the firmness of it. After reading the packaging, I am now concerned that if I install these parts, I am about to completely destroy any semblance of comfort of this fine car. Can anybody with experience comment on this setup?

[chasekin]

I love the bilsteins they're just stiff enough. You won't regret them.

[gmak]

The Black bushings are firmer and will transmit more NVH than the purple ones. I installed the UUC polyurethane bushings and coilovers and the ride is firmer - you aren't in a luxury sedan anymore - it is definitely a sport beast. While I didn't like the change at first, after fine-tuning the coilovers I have come to appreciate the greater responsiveness. If you install the black bushings, give it a chance and drive the car for a couple of weeks. I would have thought that with the BIlstein sports, and the fact that the car is not a race car, that Bavauto would have suggested the purple ones - or even the Yellow ones. I don't think that there was proper communication going on.

Check this compariso (http://powerflexusa.com/howtochoose.aspx)n of rubber vs poly vs plastic w.r.t. Powerflex.

[blarf]

I had Bilsteins + Meyle HD rear subframe bushings on my wagon -- hated them. I replaced the Bilsteins with Koni Sports (yellow) and all is right with the world. Keep in mind that even the M5 used liquid filled rubber bushings all over the place. The advantage of poly over rubber is typically the extended lifetime.

[Ken@BavAuto]

I'm a little biased obviously but I had Powerflex everything in my last E30. The only thing I wasn't a fan of was the differential mount which I though transmitted too much noise. Powerflex sway bar bushings are a great upgrade. You really feel a difference in the handling but it's not race-car dramatic like some aftermarket sets with their heim-jointed end links can be. On some of the larger cars Powerflex has discontinued the purple compound for things like the front control arms. My understanding was there wasn't an appreciable difference in NVH between the black and purple in those applications and the black is more durable so they stuck with that. In the front control arms most people don't have any issues with NVH but they do notice the bushings don't fail prematurely and the car just seems more responsive. What I always notice when going to urethane especially in the front suspension is much crisper overall feel. Especially at initial turn-in. As far as the Bilstein vs. Koni debate there's a lot of personal preference that comes into play and it seems to vary by chassis. A few of us here have used both on the same chassis cars and some prefer one or the other. So far I've preferred Koni but both are great upgrades.

[dsneal]

Got all the front parts installed and am VERY pleased with the outcome. Just stiff enough. Thanks everybody, especially Ken@BavAuto for coaching. Cannot wait to get the rear upgraded.