If you are shopping for Bilstein dampers for a Porsche, the hardest part is not choosing a brand. It is working out which of Bilstein's product lines your car actually needs. Buy the wrong one and it will physically bolt in, which is exactly what makes the mistake so easy to make and so expensive to discover.
Here is what separates them.
What does B4 actually do?
B4 is Bilstein's OE replacement line. It restores the ride and handling the factory intended, nothing more. If your dampers are simply worn out, if the car floats over crests and takes two or three oscillations to settle after a bump, and you want it to feel like it did when it was new, B4 is the correct answer and anything else is overspending.
B4 is not a performance part and does not pretend to be. On a 986 Boxster that has covered 120,000 miles, it is often the most sensible money you can spend on the car.
What does B6 do differently?
B6 Performance is the upgrade most Porsche owners actually want. It is a monotube gas-pressure damper with application-specific valving, firmer than OE, and critically it works at factory ride height with your standard springs. No spring change, no alignment surprises, no altered geometry.
The monotube construction is the real difference. A twin-tube damper mixes oil and gas as it works, and on a hard drive that aeration causes fade — the car feels progressively vaguer as the damping falls away. A monotube separates the two with a floating piston, so damping stays consistent from the first corner to the last.
If your car sits at stock height and you want it to feel sharper and stay composed when you press on, B6 is the answer. It is the majority of what we stock across the Shock Absorbers and Struts ranges.
When is B8 the right choice — and when is it a mistake?
This is where people get hurt.
B8 Performance Plus is a shortened damper. The body is physically shorter than B6, and that is deliberate: it is built for cars running lowering springs. On a lowered car, a standard-length damper spends its life sitting deep into its travel with very little compression stroke left. Hit a bump and it runs out of room, crashes into its bump stop, and the ride turns brittle while the handling turns unpredictable.
B8 solves that by shortening the body so the damper sits in the middle of its stroke at the lowered ride height, with proper travel in both directions.
Fit a B8 to a car at stock height and you invert the problem. Now the damper is fully extended most of the time, the car tops out over crests, and you have paid a premium for a worse ride than you started with.
The rule is simple: lowering springs fitted, choose B8. Stock height, choose B6. Every B8 listing in our catalogue says Lowered / Sport Suspension Only in the title for exactly this reason.
If you are running Eibach PRO-KIT springs, B8 is your damper.
What about DampTronic?
If your Porsche has PASM, or any factory electronically adjustable damping, a standard B6 or B8 will fit mechanically but will sever the car's control over the damper. Best case the system throws a fault. Worst case it silently stops working and you have disabled an option you paid several thousand for.
DampTronic dampers keep full communication with the damping control module. You retain Normal and Sport on the console and the adaptive behaviour underneath, with Bilstein's monotube construction replacing the factory unit. Everything we stock for these cars is grouped in PASM & Active Suspension.
Does it matter that dampers are sold individually?
Yes, and it catches people constantly. Bilstein dampers and strut cartridges are sold each, not in pairs. You need two per axle, four for a complete car. Every listing we publish says Sold Each in the title.
One more thing worth knowing: on several Porsche models the front strut assemblies are side-specific. The 993 and the Cayenne both use different part numbers for left and right. Ordering two of the same side is a wasted shipment and a week lost.
Quick reference
- Worn out, want it fixed properly — B4 OE Replacement
- Stock height, want it sharper — B6 Performance
- Running lowering springs — B8 Performance Plus
- Car has PASM or electronic damping — DampTronic, in B6 or B8 form
An alignment is required after any suspension work, whatever you choose.
Frequently asked questions
Can I run B8 dampers on stock springs?
No. The shortened body will leave the damper topped out at stock ride height, which rides badly and handles worse. Use B6 instead.
Do I need new springs if I fit B6?
No. B6 is designed around your factory springs at factory ride height.
Will B6 dampers make my Porsche uncomfortable?
Firmer than OE, yes. Uncomfortable, no. Monotube damping tends to feel more controlled rather than harsher, because the car settles in one movement instead of three.
How do I know if my car has PASM?
There is a damper button on the centre console, usually marked with a shock absorber icon. If you have it, you need DampTronic.
How many dampers do I need?
Two per axle. Four for the whole car. They are sold individually.
Not sure which applies to your car? Every product page lists the exact vehicles, years and options it fits. Start from your model in the Suspension menu.