[E91 Hoarder]

After reading multiple threads on this topic, I am confused. Please help me.

Context: 2006 325i (with N52B30), 168K miles, non-sport, MT, 335i sport brakes, 19" style 230 wheels on summer performance tires. The car has all original non-sport suspension.

Purpose: daily (80%), with 3-4 track days during summer (10%), spirited canyon driving (10%). I want semi-comfortable, sport handling, maybe a bit lower suspension, but not critically low.

I will be installing new shocks and struts, and considering Bilstein B8/B6 kit. However...

Main Question:
With this kind of mileage, do I need new coil springs or am I okay with the original springs? Some here say to keep original, some say new ones are needed. Confused. Do springs wear out over time, are there signs when replacement is needed? Please help me understand.

Second question:
B8 meant to run with original springs, does B6 require different springs or it is okay with original as well? If diffrent spring needed, what is recomended?

Thanks so much!

[BSM n54iS]

Keep your original springs unless you see they are cracked or damaged

I *think* you can use both b6 and b8 with oem springs, b8 though might be a little rough if you want to lower than get eibach

[E91 Hoarder]

Originally Posted by BSM n54iS

Keep your original springs unless you see they are cracked or damaged

I *think* you can use both b6 and b8 with oem springs, b8 though might be a little rough if you want to lower than get eibach

Thanks! How does B6 compare to the oem sport suspension that came on 335i? ( I used to have e92 335i with sport package and it is a reference point to me.). Ideally I'd like the sport package handling or better.

[ppointer]

I agree with BSM n54iS Unless the springs are broken, I have re-freshed suspensions without replacing springs on numerous occasions.

I have B6's on my '01 M Roadster and B4's on several other BMWs. The B6's are just that little bit better than the B4's at dealing with road imperfections. And the B4's are just that little bit better than the stock Sachs.

I think you would want to decide just what your definition of "better handling" really is. If you want good street performance, I think you'll be happy with B4's or B6's and some good tires. If you want something that kills it at the track, you might be happier with a complete system, like B8's or B12's, with shorter and stiffer springs and poly bushings.

I am very happy with my stock springs and B6's on the Z3M. The car is fine at 8/10's, and I really don't push very hard on the street. We just cruise with it on back roads, faster than most traffic but not taking undue risk. Been to Deal's Gap with it and the car was great when I drove it hard.

If I wanted to do track days, I would completely re-design the suspension and upgrade the brakes. Ideally I would have a separate track car for that, but I think I have gotten too old for that hobby.

[E91 Hoarder]

Leaning towards B6+stock springs or the B12 kit since it comes with matched springs.
Do I need all of these additional "refresh" parts that included in kit packs?