Koni makes a fine product, and I use them on my Sprinter. That being said, Koni's warranty process is a pain in the shock. You have to have "original" receipts, vehicle registration and fill in on line request. After submitting paperwork, you have to send them 50% of "retail price". Koni NA will then send you the replacements. The next step is to ship the old shocks back to Koni for evaluation of them. Then about 4 weeks later you get your monies returned. You get a letter confirming the shocks are covered, but not that your monies have been returned. Very time consuming process doing follow ups.
It's almost IMPOSSIBLE to have a verbal conversation with anyone at Koni NA.
My front shocks took 3 to 4 weeks to get my RE-MANUFACTURED front shocks, no not new shocks. Yes I did eventually get the monies returned. If the Sprinter was on the road, I might have had to buy replacements.
Again, Koni is a fine product, getting replacements is will test your patience. I thought it was a simple swap out when I bought them. I bought the shocks 8 years ago and I'm anal about saving receipts. DO YOU KNOW WHERE YOUR RECEIPTS ARE?????????? PS, I bought on-line, not locally.