That sounds really good, congrats, looks like the hard work researching and planning paid off. Would love to hear a WOT clip when you get a chance. Interestingly, it sounds very similar to my GT3 which had the full M&M cup system. That system had very similar looking headers to the ones you have except the cup headers already had a larger collector with v-band to accommodate the larger inlets into center exit muffler. Yours sounds a touch crisper and more refined though.