Crappy High sound with new exhaust setup?

[CamarLowTight28]

Hey guys
just installed the flowmaster 80 series dual kit, and custom made piece of pipe in place of the cat.It has an awesome deep roar when idling, and below 3000rpm, but as soon as u get over 3000 it has a gross high pitched sound. Is this caused by the cat. being removed? If i replace it, will it be quieter overall? If so i'd rather deal with it the way it iz. Thanx for ur time Ur answers are appreciated

[Jhonathan]

thats just the way flows sound whenever they arent broken in
give it about 3 months or so and if it hasnt changed tone to suit you then throw a high flow cat on there and see if it sounds any better

[Shadly]

I got an idea.
Resonators!!