STI Harness | eBay This part was removed off a 2006 Subaru Impreza WRX STI Sedan Manual Transmission with 161,540 miles. 2016 Subaru WRX STI Engine Wiring Harness 24020AG300 OEM 16. $209. Buy It Now. Free Shipping. Up for sale is a used STI engine harness. %0a %0a Up for sale is a used STI wiring harness. %0a %0a 2006 Subaru Impreza STI Wiring Harness - Main - Subaru SubaruPartsDeal offers the lowest prices for genuine 2006 Subaru Impreza STI parts. Parts like Wiring Harness - Main are shipped directly from authorized Subaru dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options.