What pbonsalb said, any of the major manufacturers will make a good product, the main concern would be the quality of the welds and clamps. I'm sure they're all very similar in this regard so just get the cheapest ones. I just picked up a slightly used set of MS ones last week on the forum.
As I'm sure you know, after deleting the cats the car will throw a code for increased emissions. You can purchase something like the akra delete-r which will just remove the code, or you can go with a full ECU tune. Check out this link:
http://www.m3post.com/forums/showthread.php?t=767475
You can get the best of both worlds and probably gain >30 hp to the wheels
