I Need Help Which Engine Should I Put

i need to ask a really ipmortent quistion about an engine i have a stock ls right now, i have a bout 2 g's saved up and im thinking about throwing a gsr in there but im hearing that the lsvtec is better and i really want to do that and it seems cheaper for me which one you guys think which one will give me the most power and works better cuz really im going just for strate speed so what do you guys think and can any body telll me A LITTLE BIT MOTE ABOUT LS VTEC THAT WOULD BE KOOL CUZ I KNOW LITTLE I JUS KNOW THEY GIVE OYU MAD HP AND TORQUE AND I THINK IT will be the cheapest because i already have the LS block.