Honda Accord vtec or no vtec?

how much more horse power does a DOHC vtec in a 1990's honda accord than a non vtec? im looking to buy a manual accord and tune it all up, but my friend says u really want a vtec (he has one in his tuned 93 Prelude) but at the same time, ive heard they only add like, 5 hp. i dont know a ton about engines and am learning stuff everyday, so i need some help.