whoever sold you that catback either lied or was just ignorant to the fact that it is not for a srt6. even if you had it fabbed together it would be a downgrade due tot he smaller diameter tubing then oem srt6. there is no premade catbacks for the srt6's. contact the seller and get a full refund including shipping.

we made a few different catbacks but they all sounded bad IMO while daily driving so we never produced them, i like the cat delete downpipes much better hence thats what we make for the srt6's. we can make them without the cutouts also if that what you would prefer.