i removered my resinator when i fitted my SHM Headers. had next to nothing as rear mufflers, RASPY has hell...so i fitted a jetex handy 2.5".
my system is shm headers, shm y pipe, shm cat. all 2.5".straight on my cat i have the jetex handy 2.5" a short section (9") section of 2.5" pipe, a reducer to 2.25" (also FROM JETEX) that connects to the original U shaped pipe, then split into 2, 2.25" pipes to the rear mufflers.
sounds great but do still get a little rasp from headers around 5000rpm under hard driving. but overall very nice DEEP sound....
btw the secondry kick was non existent with a 2.25 pipe, but has returned with the 2.5" handy... should be usefull to BRitish users looking to quieten there mondeos....
http://jetex.co.uk/Jetexwebsite/index2.html, part number U456300.