I just had the MSA twice pipes installed - stock manifold on a '78 280z. It was difficult to get it lined up but they did a great job - I also decided to have everything welded. It looks great and it sounds great (volume and tone) but the resonance is too much. To avoid the resonance you tend to look for the right gear and rpm (around 2900-3000) rather than the appropriate speed which can be dangerous. It's driven on sunny days in the summer so I'll live with it for awhile. Wouldn't want to have a daily commuter with this set up. I'll be taking it back in to look at installing some type of resonator but as you mentioned, it is real tight under there. It already sits real low at the 90 degree bend after the diff. Zmonkey