The APR Valve Spring System is a high performance, lightweight upgrade designed to increase valve control and eradicate valve float common on many applications. APR's design specifications called for a valve spring, retainer and spring seat combination that doesn't overpower and snap the original valves or erode the aluminum spring seat, while still maintaining exceptional valve control. The result is an advanced design that's 28% lighter yet 20% stiffer than the high performance original EA113.K04 (MK6 R) setup and is proven to eliminate the original valve train's weakest link. We call it Performance Without Compromise! Valve Springs: Weight reduction, and not necessary stiffness, is absolutely necessary to increasing valve control. The APR Valve Spring utilizes a beehive design that allows for a reduction in mass in not only the spring itself, but also through use of a smaller titanium retainer. The springs feature an ovate wire design that allows for even stress distribution resulting in better control at high RPMs through a resistance of harmful valve float inducing harmonics. The lightweight design also accomplishes accurate valve control without requiring an overly stiff spring which has been proven to snap factory valves in half. Each valve spring weights 29 grams and represents a 19% weight reduction over the orig EA113.K04 (MK6 R) spring. The result is a highly engineered design that's simply plug and play! Eliminating Valve Float: It's not uncommon to experience valve float with the factory valve springs, even below the factory rev limit. On some applications like the 2.0T EA888.1 back pressure from the K04 turbocharger upgrade has been known to force the exhaust valves open. This has been noticed on vehicles with overly weak factory valve springs and some with higher miles that have simply lost their stiffness over time. This issue accompanies misfires commonly above 5,000 RPM. In some extreme cases, valves are forced open and the vehicle ceases accelerating any further. A quick datalog of intake mass airflow and boost pressure at wide open throttle will show a sudden rise in boost pressure with an immediate loss of airflow as pressure from the open valves is pushed back into the intake manifold. On other applications, valve float can begin to occur just beyond the factory rev limit. While other components, such as higher strength valves are often required for extremely high revving applications, the APR Valve Spring System will eliminate float well beyond the revving constraints set forth by the other components. Kit Includes: Each kit includes 1 valve spring, 1 valve spring retainer, and 1 valve spring seat. Simply purchase the necessary amount for your vehicle. Most setups have 4 valves per cylinder. 3 cyl - 12 valve spring kits 4 cyl - 16 valve spring kits 5 cyl - 20 valve spring kits 6 cyl - 24 valve spring kits 8 cyl - 32 valve spring kits 10 cyl - 40 valve spring kits 12 cyl - 48 valve spring kits 16 cyl - 64 valve spring kits