Z4 3.0si coupe suspension help

[dre99gsx]

Hey guys, I see quite a bit in here for the Z4M, but wanted some quick expertise on suspension updates for my Z4 3.0si coupe. What I noticed so far is if I'm on a slope and put the parking brake on, the car will lurch a few inches reverse (upward slope), as if all the play in the suspension is getting taken up.

What is worse, is if I hit the brakes hard while doing just 3mph, the entire car shimmies and feels extremely loose, with some clunking during the braking.

I assume for starters, I need to replace the front control arm bushings. There are rubber rings that came off and got lost, which probably made things worse! I planned to go for the suspension bushings from Bavarian Autosport

PFF5-4601
Control Arm Bushing - Urethane -Street Compound - Sold as a pair - Powerflex

Are there any other components that should be replaced (bushing-wise) both in front and the rear? I'll have to do some more inspection, but wanted to get parts on order.

[GuidoK]

PFF5-4601 is a poly bushing from the manufactur powerflex.

As far as possibilities for polyurethane bushings on your car, I have a spreadsheet with most of the possibilities with links to the products:
https://audio.home.xs4all.nl/zooi/z4/bussen/xls/
I narrowed it down to the brands powerflex and strongflex, they are the best suppliers for bmw imho; both sold on ebay.
If you go for different brands, be sure to get bushings that have a knurled inner structure for bushings that act as a bearing to sufficiently trap grease. The cheaper and less developed bushings sometimes lack this and this is probably the origin of why people say polyurethane bushings can make a lot of noise.
Also I wouldnt go above shore95a stiffness (and shore80a stiffness where bushings are directly mounted on the monocoque/frame)

The bushings that are most likely to wear are the front control arm bushings (the ball links in the control arms themselves can wear too), the rear trailing arm front bushings (the polyurethane bushings have build in limiters, to limit sideways movement) and the rear diff bushing.
Sway bar bushings can wear too, and of course the front droplinks especially are a wear item.

[dre99gsx]

Perfect, that is a great guide - answered all my questions!

[GuidoK]

Powerflex also currently has complete rear adjustable camber arms (I havent yet put those in my schematic).
https://www.powerflex.co.uk/road-ser...Kit/11794.html