Generation IV Internal Engine - is it worth it????

just built a Ls3 416 i have done everything for the motor for hp as i can but changing out my 1 3/4 headers for 1 7/8, add a cutout, air lid slp one for 104 air lid, remove MAF, and a speed density tune from Speedinc and they promise me another 30rwhp... Is there any truth to this????

they are promising 30whp with swapping headers, lid, and a speed density tune, or just the tune alone?