A flash will not get you 30hp. Flash + headers maybe, but it's still optimistic. I don't think tunes are worth the money unless you also have headers.
The other thing I'd throw out there is 3.91 or 4.10 gears. You can buy the gears and have them installed for less than 1k if you find a good differential shop. Bang for the buck that's probably the highest for under 1k.
Other than that, our engines are extremely efficient. The
2012 porsche cayman R, has a 6 cylinder 3.4 liter engine and it has almost the exact HP/torque figures as the S54, and the S54 is a 3.2 liter engine.
Bang for the buck you're looking at: supercharging > gears > headers > lightening > > > everything else.
Ported throttle bodies only provide 8-12+ hp, carbon airbox is only 15hp or so. If these large, expensive but proven engine mods give this little, you can figure out on your own that almost everything else is snake oil.