2.8 motor upgrades

I've got a 91 s dime with a 2.8 v6 but i want more out of it i've already bored it 30 over with forged pistons. i dont want to run NOS not a fan of it. I'll do anything else to it though turbo, ANYTHING!!!!!! I think i am running about 175-200 hp but would like too see at least 275 if possible. PLEASE HELP ME!!!!!!!!!!!!!!!!!!!!!