I am a proud new owner of a Lancer GTS 2009. I am lucky that the previous owner already installed an Injen CAI. Otherwise, it's almost 💯 stock. However, I wanted to buy the full exhaust system. And maybe the RRM headers. But I have not seen anything said about any sort of problems with installation. I know the magnaflow exhaust needs to be cut down to fit the stock cat, which I suppose is a second choice if I have to go that route. But I'm trying to skip the extra hassle. Anyways, is it a perfect fit with the injen catback exhaust and rrm headers? Or is there extra work to be done?

I'm also wondering about the results, air pressure, etc. Do I need to do a ECU flash? Is an aftermarket ECU(i.e. RRM) worth it? Who's a reliable source to do so?

Thanks guys.