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Originally Posted by tlow98

Interesting info on the orange vs yellow. Good to know.

TC Kline SA it is then huh?

At $2k as a poverty pony spec, I am thinking no. I don't really want to invest that much coin into a daily suspension that will be used for light motorsport. I have a dedicated track car for that.

Originally Posted by gunnerxq

Koni Red's aren't the "best" but they're pretty decent. I got mine as a kit supposedly valved to Eibach prokit springs. Bought them straight from Kon before Covid when they still directly sold products.

Key to make them work are stiffer and shorter bump stops. Mine are polyurethane, trimmed them down to 1" wondering if I should should trim to .5".

When going to full compression on potholes or bumps they "crash" less then Bilstein HD's with Eibach springs.

Tried to take a page out of Fat Cat Motorsports philosophy and it worked. They weren't good when the bump stops were longer.

That said I am considering BMW yellow springs for my next upgrade. So I'll probably have to decide on different shocks.

I have worked with Shaikh at FatCat on previous cars and he is dead-on with his conclusions that bump stops are far more important than people give them credit for. If I lower the car, I intend to use the Dinan rear travel kit and short bump stops all around. I just want to use my spring rate as deep into the travel as possible.

Originally Posted by aphael

If you are sticking with bmw sport springs, stick with the b4 sport shocks (they are paired excellently, perform great, and have good ride quality) or go to bilstein b6/b8 (depending if you want longer travel). I like the konis as well and its great if you want a decent knob but the bilsteins are internally better and simpler. You can also always get them revalved for your purpose too

Stay away from the Eibach lowering springs, its a waste of money imo. It lowers without raising spring rate, so you get a lot of bottoming out. I ran them for a week before switching to another setup as it was actually slower than the stock sport springs. If you get koni yellows, I believe its HP auto that sells a swift spring conversion kit

e90 handles very well out of the box. however, depending on track, my modded 328i will struggle to keep up with my track miata. In spec form, they are faster than a lot of 335i's depending on track.

If you are autocrossing then you definitely need a LSD. For open track days its not necessary, and can be slower since lsd robs power. Again very course dependent, but its usually better to have one than not.

At this point, my options are Dinan springs because they are stiffer or OEM sport springs because they stiffer than what I have, but are very well reviewed. I was not happy when I saw the eibach springs were low and the same rate as stock.

I have some options locally for bilstein revalve, but they charge $1k a set just for the rebuild, revalve, and dyno. At which point, I can buy TC Klines like ol' boy suggested earlier.

I too have a track miata and it turns a 1:46 at my local track where a friend's E90 dedicated track car turns a 1:39. I have no intention of my daily being proper quick and sorted on a big track the way my buddy has his.

I am autocrossing for sure, but it will see light HPDE. I am leaning toward a helical/wavetrac LSD because a clutch type causes more apparent drag when turning and will require much more maintenance.

In the interest of low entry cost and guaranteed recipe for success, I think the OE springs, bilstein B4 sports, dinan camber plates, M3 arms, and an M3 front sway bar will be my choice. That setup will move the roll couple forward to reduce wheel spin from the open diff (until I can get an LSD), reduce the total pitch/roll of the car, add the necessary camber for front grip and tire wear, and not add any appreciable NVH.

[335i54n]

there is way too much pitch under acceleration with b4 and msport spring, almost feels like i can pop a wheelie. i dont get braking dive as much and eibach front sway keeps the sway under control but the acceleration squat has me contemplating just rear b8 or full b8 setup although my ride is super harsh as is with just stock b4 and msport.

[tlow98]

I will be interested to hear your review of the B4s in this application.

I just put them on our F15 X5. They work well there. No complaints. They do exactly what I thought they'd do; replace the stock suspension.

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Originally Posted by 335i54n

there is way too much pitch under acceleration with b4 and msport spring, almost feels like i can pop a wheelie. i dont get braking dive as much and eibach front sway keeps the sway under control but the acceleration squat has me contemplating just rear b8 or full b8 setup although my ride is super harsh as is with just stock b4 and msport.

Sadly, a B8 in your application will just slow the squat down, not reduce how much it squats. To reduce the amount of squat, you need a stiffer spring.

Originally Posted by tlow98

I will be interested to hear your review of the B4s in this application.

I just put them on our F15 X5. They work well there. No complaints. They do exactly what I thought they'd do; replace the stock suspension.

Yeah, I found out about two things yesterday that may impact my decision.

First, the H&R touring cup kit, which is stiffer, but very well reviewed for ride quality. Also, through connections I have, I can get it for only $100 more than sport springs and Bilstein B4. It is however lower....

Second, there exist rubber spacers for BMWs to increase ride height. If I am running the dinan camber plates, that gets me 5mm back up front and I can get 5mm spring spacers for the rear. This should keep the total lowering of an H&R cup kit under 1". There are even options if I need more height than that.

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Just to wrap up this thread, I went with the OE M-sport springs with matched Sachs dampers, Turner Motorsport Fixed Camber Plates, M-sport front bumpstops, E36 M3 rear bump stops, and Whiteline rear subframe bushing inserts.

This setup rides like a stock daily should, but on track it rotates aggressively under braking. There is enough front camber to prevent excessive tire wear with an enduro 200tw, but not enough to damage a 500tw daily tire. I would not suggest anything stickier than a harder 200tw with this setup as I can already find the bumpstops under aggressive cornering.

For casual HPDE and daily driving in a city with crap roads, I am very happy. The only thing it needs now is a LSD.