welcome.
as already stated, gm truck coils?
not necessary at 350hp.
ive got 20yr old stock coils igniting 600rwhp.
so, they are obviously more then capable.
dont replace them until your spark runs out.
if pursuing 350hp, the standard turbos should be very close to that.
ive have heard of more, but you may not want to push it.
if aiming higher, then look at turbo replacement.
theres alot of info on this forum, and im sure you'll waste hours reading.
good luck with all your mods, and keep is updated.