I got some GKN boots from eurocarparts a couple of years ago, they only lasted 50K miles. Every genuine Audi CV boot I've had over years have lasted 100K to 150K. ECP boot cost just under £20 but the Audi boot cost just over £40 and you need to buy the hub bolt, as it's not included in the Audi kit. After looking at the quality of the Audi boot compared to the aftermarket boot, I would never buy aftermarket again, not worth the time & hassle for an extra £25 to buy the better boot.