I'll second the above, if going for a Powerflow, you might as well save your pennies and get a Peco backbox from Halfords. Build quality is atrocious and the drone is horrendous. I've heard good things about Blueflame, apparently they actually do OEM work for the likes of TVR, however I'm happy to corrected on that one. I'm also keen on Miltek (no better way to make an R32 sing), although I've heard they have a tendency to drone on the GTi and the APR is the better option? Again, happy to corrected on that, just what I've read whilst doing my research.