Rough road suspension for 986 Boxster?

When I bought my 2000 Boxster it already had Bilstein PSS9 coilovers and Eibach sway bars, which is great for smooth pavement, but I have been daily driving it and it's really not the best for that.  It's stiff enough to pick the front wheel up going into a driveway so the abs makes the brakes not work, I have blown a tire from a pothole and several times pulled the fender liners loose from slamming it into the bumpstops, and there are big enough jumps on the freeway that it will definitely get the tires off the ground and it's hard to keep the steering and accelerator inputs steady when I'm bouncing my head off the roof and getting launched out of the seat.  

Should I just look for stock springs and maybe some 16" wheels to replace the 17s? Or is there a better option.  I know it's really not the appropriate car for California roads but I don't even think I could find a boring car to replace it for less than 2-3x the price that would be near as reliable.

What are the spring rates like vs. stock? The Boxster has good enough geometry that you shouldn't need super-hard springs. On my Toyobaru I'm running a BMW-style combination of softish springs and hard bars, and while it definitely rides a bit stiffer than stock it's far from a skateboard.

For damping, this might be a good use for driver-adjustable shocks that could be set hard for the track and soft for the street, but just softening the shocks to match softer springs might be enough to get the job done.

If hitting the bumpstops is causing the wheels to tear the fender liners out, you need to modify the fender liners for more clearance or get longer bump stops.

I don't have any experience with the pss9s but honestly that sounds like a suspension issue. Too low, damper settings way off, and/or blown dampers.

To directly answer your question, my boxster was all stock with bilstein B6 replacement struts. It was great on the road and handled rallycross without ever ruining any fender liners. 16" winter/rallycross wheels and 17" summer wheels both did fine.

I don't have any direct Boxster experience but it sounds to me like a poor suspension setup or bad parts. If it's affordable, I would do a reset to "stage 0" as in replace bushings springs and shocks with factory or factory-ish parts. The base or S factory suspension are both really good and should give you a fun sporty ride without being harsh on the street. Maybe upgrade the dampers while you're at it to something stock plus like the bilstein HD (i loved those on my Volvo) but not full race stuff. So many people thing stiffer equals better but it's really not. Leaving compliance in the suspension not only makes it more comfortable and usable but can actually be faster. All that time with one or more wheels in the air reduces your grip massively. 

Sounds like your spring rates and damping are way off for street use. On my Boxster I rebuilt the suspension and put in the B6 (I think, it was one step up from stock damping) and the rest-of-world M030 sport suspension springs on the car. It was pretty firm, but the behavior on rough roads was nothing like you describe. If your roads are pretty bad, then go back to stock or a set-up like I had.

Another option is Koni Sports + stock or RoW springs. I really like the sports on my 987. 

If my google search was showing me the correct shocks then those are double adjustable so the first step would be to back the damping off.  Your description sounds like at least the rebound is way too stiff.  If that doesn't get you the improvement you're after you can try softer springs on the same coil overs.

My 2.7 on original (worn) suspension is totally fine on LA roads. Maybe a bit too soft and worn actually, I get into the bump stops a lot... but crashy and harsh it is not. The conti ECS 02s are pretty soft as well which doesn't hurt. 

I heard the stock suspension is quite compliant on these. Maybe try that? I'm sure you can get a used set of stock stuff for pretty cheap to test.

APEowner said:

If my google search was showing me the correct shocks then those are double adjustable so the first step would be to back the damping off.  Your description sounds like at least the rebound is way too stiff.  If that doesn't get you the improvement you're after you can try softer springs on the same coil overs.

Without knowing anything about the setup, ride height, spring rates, etc., slamming into the bump stops is some combination of too little compression damping or not enough ride height. Of course the magic of double adjustable dampers is it could be too soft in compression *and* too stiff in rebound.