Thanks, I'll problably go w/ DC 4-2-1. Now when you mean chambered what are you talking about? Also where is the ECU located & isn't 98 Gsr's OD2? The exhaust will problably be the WS. So does it has a nice deep sound. It won't be loud when cruising will it, or only when I get into it. That's how my Thermal is on my Si.