Suspension issues, researched thoroughly and still have no idea what to do

Sixbanger

Specialist
Jun 20, 2017
77
18
0
Ride
08 135I
Car is an 08 135i and I've owned it since day 1 and ordered it when I first saw it in Motor Trend in 2008. Love the car to just get rid of it, but the suspension is a never ending problem. Steering is very sluggish and not as quick as I thought it'd be, especially with the modifications I've done over time to the suspension. I understand with modifications that the car will feel totally different and ride totally different, and I'm fine with that. Car is over due for an alignment and that's priority on my list this week. The suspension guy that installed a majority of the suspension mods is 100 miles away one way. I dont have anyone local like the suspension company I use in Miami. They're very familiar with my car and race every week at the track. My point is they know what they're doing, but also very expensive. The following are suspension mods I've done to the car over the years I've owned the car:
Will TC Kline white springs fit my dinan koni struts?
E90 M3 front sway bar
Dinan yellow koni struts
Swift R spec springs 205 spring rate up front 500lb rear
TC Kline front and rear monoball kit
M3 rear subframe bushings
M3 front lower control arms (just the front L+R tension struts)
No camber kit
 

camberadam

Sergeant
Feb 15, 2017
257
106
0
Baltimore
Ride
Tasmin Green e92
IMO the sluggish response would come from the steering rack. Everything you've done would improve handling & driver feedback, but none of it is going to change how fast the wheels turn L & R. You may be able to improve the response w/ a more track focused alignment, but you'd have to find a happy medium between responsiveness & tire wear.
 
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Jeffman

Captain
Jan 7, 2017
1,469
524
0
How many times have you changed the power steering fluid? Mike Miller of BMWCCA fame suggests changing it every 30K miles.
 

LessIsMore

Specialist
Aug 21, 2017
56
22
0
Ride
09 535i
so is there an actual issue/problem, or just trying to get quicker steering?
When you get it aligned, have them set camber/caster more aggressively for better turn-in
Also runflat tires with super-stiff sidewalls will help turn-in sharpness/feel

But as far as 'sluggish' steering, the only way to help that is by getting a different rack. in fact, wider front tires, etc. can make the wheel heavier to turn.