I know the apollo FMIC, I actually had it on my last 300zx. It was nice but very inefficient. I am thinking of going with the stillens because they improve turbo response as well providing the most power. Another problem with the apollo is that i blocked airflow to the motor causing it to overheat (the z is already a very hot car to begin with). So I am pretty sure the SMIC from stillen is the way I will go this time. Plus no one will ever see them, so I can keep a sleeper look

 

Good choice on the exhaust. I also have an Hks exhaust for my scooby and it sounds nice. Also don't listen to people who say it's not going to last long, mine is holding up 100%. It is still shiny as hell and the welds are top notch. Hks has a good reputation.