For a manual trans and a street car an FR-500C is a good choice. For my drag car it's holding back 100-200rwhp on the top end. The shortest possible runner is 10 inches, which would by all calculations puts peak power at 7,250 max. You would gain a massive amount of top end power with those cams and a shorter runner intake. Your dyno shows this, by basically going flat after 6k (I assume you are still using trumpets and this the reason for the lower rpm). I'll be spinning to 8k, and as such would lose a massive amount of power. I should be 1300-1400.For a turbo street cobra running a modular with gt500 heads, the fr500c intake is as good as you'll get. Unless you spin 8500rpm, you can't get much more top end from other designs but in the process you'll lose tons of low end.
If I ran a Sullivan or sheetmetal unit, I'd have 150wtq until 4000rpm. I'd have a bit more top end but not worth the trade, maybe 50whp up top. The fr500c flows huge volume for its velocity. On paper/mathematically it would take 8000-8500rpm with boost to become a road block.
I'd run that fr500c. You can also get smaller internal port holes/plumes if you need 8000rpm.
I plan to rev mine to 8250. On paper it should peak at 7800 and barely taper down 2% by that point. It'll be mid winter when I go Holley efi stand alone and a magnum 6060 trans so I can safely pull it that high but I can keep you posted how it works out on these (long) plumes.