Stock gt3582 with mods will make 400 on 98 easy. Just need the right mods. Also need large supporting mods. I made 410rwkw on 98 and 480rwkw on E85 with factory turbo both 18psi.
I even made 400rwkw with 15psi (98) on factory turbo with BF F6.
You dont need to upgrade , just modify and have large inter-cooler and intake.
3576 run out of puff like emphysema