[E90ALLMANUAL]

My car: 2011 E90 328i sport package 57k miles
Mods before insets
1. M3 front control arms
2. Whiteline front sway bar(27 mm)

After tracking and Autocrossing my car, I noticed how loose the rear end was. And improving the front suspension made it more noticeable.

I finally installed the rear inserts and realized that this should had been the first upgrade. Everything about the handling is better now. The front and rear are now working together. It has been only two days of daily driving but Sunday I have a track day and I will update.

So far no downside. If you are thinking about doing it, go ahead, it's worth it.

[turo]

I hadn't heard of these before. Just did a quick search, so you install these instead of M3 subframe bushings? Is the advantage (over the M3 ones) just installation difficulty?

[weehe126]

Originally Posted by turo

I hadn't heard of these before. Just did a quick search, so you install these instead of M3 subframe bushings? Is the advantage (over the M3 ones) just installation difficulty?

And the cost.

[E90ALLMANUAL]

A full bushing replacement, in theory, should be better. But I don't have anything to compare to.

I think the real question is how much better? Enough to justify the price and labor?

[Tom Droze]

I did this mod too and the improvement in handling was quite noticeable. The cost of the inserts are less than $100 and can be installed (DIY) in less than two hours. Given the bang for the buck, this is a very worthwhile modification in my opinion.

[gtaccord]

Yep.

[feuer]

Only M3 bushings do not make finantial sense.
They are expensie to purchase and the labor involved is more intense compare to aftermarket solutions.
I have the inserts as well and I'm happy with the result.
My 275/35 on 10" et25 was rubbing in hard turns because of stock bushings deformation.
Not anymore.
So for $50 and about 90min of my time I can not complain at all.

[justpete]

Originally Posted by E90ALLMANUAL

My car: 2011 E90 328i sport package 57k miles
Mods before insets
1. M3 front control arms
2. Whiteline front sway bar(27 mm)

After tracking and Autocrossing my car, I noticed how loose the rear end was. And improving the front suspension made it more noticeable.

I finally installed the rear inserts and realized that this should had been the first upgrade. Everything about the handling is better now. The front and rear are now working together. It has been only two days of daily driving but Sunday I have a track day and I will update.

So far no downside. If you are thinking about doing it, go ahead, it's worth it.

Great advice, these minor changes will always make a big difference in handling. Definitely more difficult to upset the car in a turn now.

[ajsalida]

I've had the inserts for couple of years now. Definitely a good upgrade as long as the rest of the suspension is not too extreme.

However I recently installed Strongflex tension strut yellow poly bushings in front (XI) and it is clear I crossed the line as now the rear feels relatively soft again. Will probably go solid or delrin/solid rear subframe bushings next and skip M3 bushings.

I had Koni/eibach when I installed the Whiteline inserts, big improvement. Installed rear M3 bar same time. Then front UUC bar. Then Powerflex rear upper shock mounts (yellow). So far so good. Then the Strongflex front bushings (huge improvement) everything else is now stiff enough where the rear subframe began feeling a bit soft again.

Will probably wait until I do LSD and some M3 arms back there, really not looking forward to a full RSFB job.

[mlifxs]

I'm another fan of the inserts. They make a difference and it's pretty hard to screw up the DIY, since even I managed it without mishap. There's a nice DIY on 1addicts that fills in some details not covered in the Whiteline instructions.

Originally Posted by ajsalida

However I recently installed Strongflex tension strut yellow poly bushings in front (XI) and it is clear I crossed the line as now the rear feels relatively soft again. Will probably go solid or delrin/solid rear subframe bushings next and skip M3 bushings.

Thanks for the Strongflex reference. Never heard of them until now. Checked out their stuff...pretty interesting and prices seem compelling. Maybe a front sway bushing purchase in my future

[ajsalida]

Originally Posted by mlifxs

Thanks for the Strongflex reference. Never heard of them until now. Checked out their stuff...pretty interesting and prices seem compelling. Maybe a front sway bushing purchase in my future

Sure thing. They are really the only option in front for XI bushing/arm upgrades, M3 arms won't fit and nobody else makes poly. One guy got some custom mono-ball bushings made for his tension struts but I do not think he's installed them yet. Actually that is not entirely true, one other guy trimmed RWD TS bushings from Whiteline and they fit.

Anyway I was hesitant to order from Poland but they shipped immediately and got here in less than a week. Good value and excellent upgrade. Bear to install. I had one of the fluid bushings fail and no way I was going to put OEM back in, glad I went with the Strongflex. But then as I said the balance of stiffness shifted and now the Whiteline inserts + OEM RSFB are the soft spot. Not bad at all but I can feel the difference F vs R.

There are a few threads on Strongflex bushings here and in the XI section if you want to read up on others' impressions.