I have a 99' GS-R and I'm in the market for a good header and exhaust system. I've been having some trouble finding good information on the true differences between a 4-1 header and a 4-2-1 design. Right now I'm between the DC 4-1 header and the comptech 4-2-1, as well as both companies cat-back exhaust systems. The cat-back needs to provide power(duh), but not sound too loud and reedy. I would appreciate your opinions and experienses with both of these systems as well as other possible options.

Just so you guys know I plan on going further with the motor in the near future, with cams, ECU, fuel system, etc. But I/H/E is first.