Any good Muffler Shop SHOULD have the equipment to flare pipe to match whats factory so its really what you want to go with on piping
Frankly and this is the more expensive way to do it but Id go to a shop and have them go from as close to the resonator as possible and put in an actual "Y" pipe which is usually 2 1/2 and continue that size pipe to a set of Flow 40 series or Magnaflows of the same equivalence, recommended by most if using duals, and finish with a nice set of tips
Purplehazier'* Dual Magnaflows can be seen/heard here - Magna Flow Mufflers and Hi-Flow Cat on Flickr - Photo Sharing!
Danthurs' Dual Series 40 Flows here - videos :: exhaust video by dthurs2000 - Photobucket
you can always PM either for more information but maybe that will help some... good luck