Strange! I just returned from vacation and hadn't driven my car in a while. Really noticed the vibration sitting at traffic lights. That bit of rasp I have has not gone away unfortunately. It's all below 3K and only at WOT. Above that, sounds great. I'm actually contemplating a full FI exhaust now.

 

A small update, most of the rasp has gone and the car is a hair quieter overall. Still have the vibration, still need to fabricate a bracket and get the car tuned but much happier than I was right after installing them. Part throttle is definitely much improved and WOT will be improved once I get the car tuned.

 

Small update, a 370z forum member posted that his FI RHFC's came apart at the weld. I'd keep an eye on them if you have them installed. I will admit, the car sounds fantastic.