Flowmaster exhaust

I know that there has been plenty of threads on here about exhaust systems, so why not another?

I have an '03 Ram 1500 5.9L. I am pretty sure that the Cat is blocked or obstructing my exhaust flow. If I let it warm up in the mornings longer than 5 min. the check engine light comes on and the truck runs like crap for a few miles before it smoothes out. Eventually the engine light goes off and all is well. When the light is on trouble code P0308 will display. P0308 is a cylinder #8 misfire. About every 6 months I end up replacing that particular spark plug because the truck keeps running like shit.

Anyways this all leads me to believe that the catalytic converter needs replaced. I plan to hollow it out to see if it improves the trucks performance. My question really is should I replace it or leave it gutted. I know the legal aspect of it all, but truthfully, I dont care about the law if it improves performance. Also, I plan to put a cat back exhaust sytem on it as well. I like the sound of the flowmaster, but they make different types. I don't want it to be too loud, but I want that throaty growl too. What do you guys recommend. I'm open to your criticizm.

Any advice. Anyone.

flow master 70 series, its the quieter ones, but still has a nice growl under acceleration, almost no drone at cruising speeds.

and about your cats, have you ever thought about a cutout? get one before the cats, and u dont have to worry about them anymore (except for when u run them closed)

Thanks. I was thinking either the 50 or the 70 series. I'll probably shoot for the 70. since I don't want the loud at cruising speed. I had a 40 series on a suburban and it drove me nuts, especially with the side exhaust. Sounded cool though.

I've never heard of cutouts. I'll research it.

a cutout is like a y pipe, one end of the y keeps goin on to the muffler, and the other just ends short there, like a dump, but has a cap to open or close it, so when its open, u bypass the rest of the exhaust.

i got a 04 ram w/ the 5.7 and i just recently did dual flowmaster 40's w/turn downs right after the mufflers , was expecting it to be super loud but to my suprize at at idle its got a pretty mellow rumble, but when you get on it ,it sounds like a damn nascar, 40's are the way to go . . . in my opinion