Well, I the R1 exhaust and Front/Y Pipe is on and all I can say is WOW!
O.K., reasons I love this exhaust are:
1. Weight - The reduction in weight should not be understated. I could literally feel the weight reduction as soon as I left the shop. It is amazing how much of a difference it made, the Z now is much more tossable. It is not RX8 tossable, but the gap has narrowed significantly.
2. Power and Sound -I can feel the power increases, especially in the mid range to upper end of the power band. I did not dyno her and do not have plans to (far too little time), but I would guess the total set up (R1 and Y Pipe) added between 15 and 18 HP... give or take...... The sound is intoxicating. The Z definitely has a growl to it now, but it is not too loud. It sounds exotic aggressive, if you could imagine that. I LOVE it....
3. NVH?? - I had to add this because any NVH I experienced prior to adding the exhaust are gone... The Z revs so much more willingly now. It is easy to find myself spending the majority of my time from 4k to 6500 RPMs just because it revs so effortlessly now (and sounds great). This really is how the Z should have come from the factory!!
I attached a few quick rough pics for your viewing (sorry about the dirty garage floor; it is time to redo the flooring...). I got the thicker, rolled tips. If you have the $$, I HIGHLY recommend this setup. Props to Bulletproof and IntensePower!