I am very pleased with the AEM Charge Pipe and Recirculation Kit. I recently installed both on my 2015 WRX and immediately noticed several positive changes. First, you get a noticeable gain in horsepower in the mid-range and second, your boost increases far more rapidly. A third benefit is the audibly noticeable increase in turbo-spool, which sounds amazing. I installed an after-market blow-off valve to replace the stock BOV. It works very well with the Charge Pipe. The installation of the pipe was plug-and-play no MIL or codes thrown.
Prior to this purchase, I installed the AEM's Cold Air Intake and Strut Tower Support. In my view, AEM's products are engineered well, fit perfectly and come with simple DIY instructions. Good stuff...and by the way, if you keep your engine bay clean and sharp, AEM's products will serve to only compliment. Thanks folks.