Hello all, I'm new to the forum which I find very useful. I have a 2010 Audi S5 with the natural aspirated 4.2 V8. The only purchase I want to make for the engine is an aftermarket cold air intake to replace the stock one, as I've heard nothing but good things, ensuring that it does not damage the engine in any way but rather improve it. I heard K&N and APR are really good and often used. APR is $500 with the filter and its own carbon fiber cover, replacing the stock airbox. The K&N only had the filter alone which is $70. I have no problem spending $500 but I just want to know which one will Have the bigger improvement in any way. I appreciate any help, thanks!