when i got em i also dunno wats the diff...and i never drive b4 my 4g91 as stock...b4 transplant edi put in 4g93 cam..when i dyno its wit 4g93 cam and a hks open pod...cap ayam 2" muffler...106hp on wheel...so i think the 4g93 cam does somewhat make some diff...since tat 106hp convert back to crank quite higher than stock 110hp 4g91