You should still see benefit from a heatshield if you still have a FMIC. Turbo heat will rise and fill your engine compartment. It will reduce stress/heat on your electrical and cooling hoses - and possibly reduce the heat wear on those hoses from prematurely cracking over time.
One thing about a high performance engine. Heat in unwanted places is NOT a GOOD THING! (insert Martha Stewart jokes here)
ok. My .02.