with no cats, it wil just sound bad above 3k rpms. when i say ricey, i mean raspy, rackety, and not DEEP and POWERFUL like what you're hoping for. it won't sound like a fart can exhaust muffler or resonator, but it isn't what you're thinking about probably. i'm sorry, but other can varify this as well. i'm getting ready for a supercharger, so i'm going with a 2.5" off road x pipe as well. i don't care about sound much though, mostly power.
any cat-back system you get won't sound that bad, unless you go with flowmasters which aren't great for power and definitely don't sound as good as magnaflows... try to avoid a 2 chamber muffler, go with 3 if possible. it'll mitigate the sound and that means it'll sound better.