As someone who started with a 3.4" pulley, 1.0 tune, and basic intake/exhaust items for ~$500, I was running ~13.9 in my GTP consistently enough to win a street bracket class at my local track before. It's all in how people maintain their vehicles and listen to what it needs to run cleanly.
After that, I had a cam-only, non-intercooled, stock heads setup running 12.7's at over 110 on street tires and a slipping $75 junkyard transmission. That's something most people wind up trying to accomplish with all 3 of those upgrades filled-in and more. The range of possibilities is down to how much time/effort & smart application of money you apply.
Throwing a pulley on and not cleaning your MAF or other maintenance can have junk results or make it run like a rocket, but taking care of all your components & systems will put you more to the rocket end of the spectrum more consistently... Especially when you're a poor college kid maximizing the free/custom mods, as well.