ok, if they have a data logger and log the run in with the AFR, then they could be onto a good thing. i just dunno about tune shops and shops that tune on the side.
just remember to ask them what main jets, needles, needle hights, pilots and turns on the air screw are, when you pick it up and relay the info here.
and to the original question for more power, running meth will be the cheapest option because your other options are more port or more engine.