Hello, I am a noob to the Subaru world and I have a few questions. I want to replace my exhaust system but Im having trouble deciding what to do. I want to replace my whole system. The invida q300 looks awesome but do I need to replace the stock cat with a high flow cat? Does the Q300 come with a downpipe? Can I tune with a Cobb access port using this exhaust? recommendations for other exhaust systems? I have a stock 2011 WRX limited. I appreciate any information you can give me!!