You want the exhaust designed specifically for your car. With a catback system your basically concerned with the fitment of the exhaust canister with the rear bumper (specifically when concerned with hatchbacks). If your cars an HX and your just running the B-series exhaust manifold (header) into the stock catbacks flex joint, that should still work with an HX catback. I've never tried it myself but it stands to reason. I'm not sure what you had to drill though?