1994 Sierra Engine Tune-Up, Maintenance

Hey everyone, i have a 94 sierra 5.7L 350 V8 with around 188,XXX miles. I'm lookin' for some ideas on what i should do/replace to get a little more give out of this truck. The tranny was replaced about 2 years ago and shifts great but its really the motor. It was replaced around 33,000 miles so ive got around 155,XXX on the motor. What do you guys think i should do to improve horespower because its really draggin and real sluggish. Ive been told spark plugs, plug wires, new air filter, air intake, etc. Anything else I could do without blowin' my wallet?