I've had mine for about 5 yrs / 40k miles, the last year on 500 / 300 springs. I haven't noticed any degradation in the damping. I believe they have a lifetime warrantee, except for motorsport use. They are rebuildable, but it isn't cheap, IIRC about $100 a corner, but you can get any valving you want. Next year, I might be moving to a monotube setup, but I'll keep my reliable konis w/ GC as backup spares.
I got mine installed when I first got the car 10 years and 50k miles ago. My car hunts alot, I've it aligned a couple of times, once with a Lanny and then back to factory. I've had most of the front end redone as well so it got me thinking shocks for some reason since it's been a slow degradation lately. Also when the pavement's smooth it tracks pretty good but anything less and it feels off center. If it's not the shocks then what's left?
Looking at your location is pretty funny, I got the car at Mazda of Newport when I was stationed there, I lived in Middletown!
Well KONI is a very respectful brand. They offer lifetime warranty which I already used two times (last time a month ago).
Go to they website and follow the process!
I believe that if the suspension has degrade they can replace them for free.
Call they customer service and ask! Mr. Stoney was very helpful...
Usually you order new ones in dealer price $88 each (I think) and then you send yours. If they are indeed defective they refund your money!
Very useful since you don't have to change shocks two times...
Btw even if they don't refund your money (they did both times for me) you can sell your (proven) good socks online and probably be even...
My car hunts quite a bit on uneven roads. In my case, I know it is due to alignment (CSP auto-x numbers) and not the dampers. In my case, I using about -2 degress camber up front with 1/32 total toe in. This makes for a lively front end that tracks the imperfections in the road. The flip is that the feedback is very good which is important when trying to get every last bit of grip from the front end when diving into a turn at auto-x. If you are using less toe in than the factory spec, the alignment might be a big contributor to the hunting feeling.
Also, when the dealer or whoever aligns the car to factory, the variance is very large. For example total toe in is rated at 0.12 inches +/- 0.15 inches. This means you can have a total toe of 0.03 inches OUT to 0.27 inches IN. That is a huge difference! Camber values for a 14" ride height car are 24' +/- 1 degree. That translates to +1degree 24 min to - O degrees 36 min. Again, a Huge difference. To the tech, the car shows up green on the alignment machine. Take a look at you alignment numbers if you have them and see how tight the numbers are. You may be surprised.
I'm not saying to go out and get another alignment. But it is worth investigating before you start spending money. One thing you can to do see if you are having not enough toe in is to adjust the lock bolts on the tie rods. By changing both sides one full turn will change toe by about 7mm (.28 inch). So if you add one full turn to both side, you will certainly make a difference in the handling of the car. If you try this and your hunting goes away, then you know that alignment is a contributor to your issue.
Currently stationed out here, moving to San Diego soon! Can't wait for the year round good weather.
Thanks Chris and Bruce, the hard part I've been having is finding a good shop that will take the time to dial it in for me but I just called around and got a few numbers for people who have set up a few racing Miatas so I'll give them a call on Monday and see what kind of feeling I get from them and schedule an appointment.
Good info on the replacement, I went to their site last night and found out they do have lifetime warranties to the original owners (which I am), don't know where that receipt would be though ... did they give you a hard time about it?
Bruce ... what ship you going to? I'm here in Millington so I might have written your orders!