Using Your COBB Cat - back Exhaust: This exhaust is designed to be used with 2011 - 2014 Subaru WRX and STI Sedans. It's ready to run with COBB OTS Maps right out of the box. Installation: It requires an intermediate level of installation effort. Refer to the included installation guide for step - by - step instructions. Note: If you have a stock j pipe or downpipe, you'll need to buy the GrimmSpeed Subaru Stock DP to Aftermarket 3 in. Catback Adapter p/n 077046. Maintenance: Since it's made of 304 stainless steel, it's quite durable. But it's a good idea to regularly check the TIG - welded joints for any signs of wear or damage. Clean the exhaust tips with a mild cleaner to keep them looking shiny and to maintain the etched COBB logos.