[Wongway]

I'm planning on a suspension redo of my 2011 328 Xdrive Sedan over the next year.

Current plan is
ZSP or Performance Springs + Koni FSD's (2100-4123)
What Labeling on the Springs should I look for on either?
D5 front / D4 rear for ZSP? T? front/rear for Performance?

M3 rear subframe bushings.

M3 rear sway bar.



I'm to understand none of the M parts like Control arms work for the front?

Any recommended front sway bar to pair with the M3 rear?

Are there any other recommendations for the front? Or mostly to leave as is?


Goals for this is rather modest. It's mostly to get rid of the slamming of the car over potholes since the car sees winter driving close to 5 months of the year, and the rest avoiding potholes that they never seem to fix. I didn't want to drop the car much if possible, so I figured the Koni FSD's would be a good compromise in sporty handling and pothole friendly.

[Sidewinderpb]

M suspension components are not compatible with xi fronts.

I think UUC makes an xi front sway.

[Wongway]

Originally Posted by Sidewinderpb

M suspension components are not compatible with xi fronts.

I think UUC makes an xi front sway.

If I'm not mistaken, I just need to make sure I have stock bushings to use with those right? (The UUC front sway)

[Sidewinderpb]

Are you referring to the D bushings on the sway bar? I would think that they would come with those. If not, they can't be very expensive.

[ajsalida]

OP these questions have been gone over many times here and in other susp section please use search function.

UUC front bar comes with bushings.

Start with a thread titled "i springs on xi" for ZSP on XI then there are many threads on XI use of UUC bar, M3 subframe bushings, and rear M3 bar or not.

Lot of people not thrilled with FSD's on BMWPS.

[Wongway]

Originally Posted by ajsalida

OP these questions have been gone over many times here and in other susp section please use search function...

That's the problem. I have, and had to take a lot of things into account. Some early reports of FSDs were harsh. Later ones seem to find them much better.

I've seen that Xi springs are stiffer than even the ZSP springs.

I've seen people recommend not to use lowering springs on FSDs, however, what I've been told so far is that the Xi springs are too tall for the natural valve rate change of FSDs, so people will opt for slightly shorter springs. (and I'm wondering if that's why some early adopters found them too bouncy)

So yeah, I've done a truckload of searching...

What I'm hoping for is more recent opinions of the FSD's and what type of springs were used on their Xi's.

[SaviorXi]

I have this done on my car and it is absolutely 100% perfect even on NJ roads. I am now confident to say that I love the comfort and handling of my xdrive. It only took 2 cars 4 years and many thousands on setup after setup to get the best. Pure perfection

front
-Strongflex 031528B Polyurethane front control arm bushings (amazing)
- UUC swaybarbarian front sway bar
-M3 front strut tower brace
- Meyle HD front endlinks
- Koni TCKline xdrive shortened adjustable front struts
-- Eibach 335i pro springs front
rear
-M3 rear subframe bushings
- M3 rear sway bar and bushings
-TC Kline Koni rear externally adjustable shocks
- Eibach 335i pro springs rear

[Wongway]

your Xi will have different characteristics than mine, so some of which might be overkill for me.
@SaviorXi
I've seen varying reports of this;
Since I don't see you have LSD installed, how's your rear end with the M3 rear sway bars installed? I've seen a few people comment they get a bit of oversteer with it because the rear is so tight. I'm sure I probably wouldn't get that since my power output is much lower.

[SaviorXi]

Originally Posted by Wongway

your Xi will have different characteristics than mine, so some of which might be overkill for me.
@SaviorXi
I've seen varying reports of this;
Since I don't see you have LSD installed, how's your rear end with the M3 rear sway bars installed? I've seen a few people comment they get a bit of oversteer with it because the rear is so tight. I'm sure I probably wouldn't get that since my power output is much lower.

With the rear M3 sway and rear bushings paired with the front UUC sway the oversteer is minimal if any. I have zero need for a LSD. The car is balanced, flat, and predictable.

[Wongway]

Thanks for the info on your front pieces.

Down the line, if what I'm initially doing isn't enough of what I want, I may look into your front sway and front control arm bushings.

[thegrinchboy]

2011 335xi with:

UUC F/R sways
Koni Yellow F/R struts+shocks

Initially: Eibach Sport. Then: ZSP D6/D4. Now: Dinan F/R springs

Depending on personal taste, road conditions, and purpose. Good luck.

[Julian2485]

Originally Posted by Sidewinderpb

M suspension components are not compatible with xi fronts.

I think UUC makes an xi front sway.

I've been reading the m components don't fit in front xi but I know brentuning had e93 m front swaybar on his front xi. I don't know details on how he did but would def like to know how he did it