I spotted a set of Stainless Power, with high flow cats to connect to stock exhaust for $687.74 (w/coupon and free shipping) from AutoAnything.com. Folks seem to like them but like anything there has been an issue now and then. The latest I read was gaps in the flange weld. Has anyone had any experience with them or have heard anything elase good or bad? I know a tune will get the most out of them but will the engine throw any error without a tune?