Very, very limited. Really, 130hp is pretty reasonable. Were you upgrading from, say, a '96 Tracker, you'd be pleased as peaches with what you've got. I'm skeptical of any of the half-way "cold air induction" type deals with cone filters sucking warm underhood air versus your stock airbox sucking cooler fender air, and I haven't heard of anyone experimenting with bigger injectors up to this point. For measurable improvement, you'll be lucky to get more from anything other than exhaust work.
That said, and I know it doesn't answer your question exactly, but if you stumble on a wrecked V6 Tracker or GV.....seriously consider it. Mileage drops, but I've heard overall satisfaction goes through the roof.