Need some serious power, any ideas?

No internal upgrades will make it sound any different other than a big cam which you don't want. To stroke it means new pistons, rods and crank and usually clearencing the block for the longer stroke. That will give it more power but not sound different. You can run nitrous on it the way it is as long as you stay at 75 hp or less and run colder plugs and high octane gas. If you want more a forged crank, new forged pitons with lower ring lands, bigger fuel pump and injectors and a tune. An H pipe will only help a little with reducing the popping sound we get but won't add in power with these motors (even firing). Also you can run a turbo or blower on the stock motor, just keep the boost below 11 psi.

gears. if going s/c in the future i would say go with 3.73s. i have a 3.8 n/a and run 4.10s and i love them.