As far as I can tell, there's very little in the way of back-to-back cold air intake testing carried out so a direct comparison is very hard to find. The EVOMS and Revo intakes both use a single piece pipe which is supposed to help reduce turbulence (a.k.a. resistance to air flow) into the inlet, where as the RamAir kit uses sections of pipe and silicon hose which does the same job, but a little more involved to fit (about 5 minutes more I'd guess).
If you go on the RamAir website (
www.ramair-filters.co.uk) and use the code 10OFF at the checkout, you get a further 10% off! I've been more than happy with my RamAir kit in my GTI and will likely opt for it again for my Golf R as I can't see how paying twice as much for the Revo/EVOMS kit is worth it.
The only reason (in theory) I'd consider another kit is design, and the only one that differs is the VW Racing one. This one utilises the original air duct under the slam panel and also has one less bend in it (it goes straight to the back of the engine, then a 90 degree bend) where as the Revo/EVOMS kits both have an addition 45 degree bend after the filter. Also the VWR intake is an enclosed system made from carbon so less prone to heat soak too. But again, it's a pricey kit for what it is but it's the only other option I'd personally consider over the RamAir kit.
