a viper will not blow L7's if you set your gains properly. any amp can blow any sub, you gotta watch your gains. that viper or any 2000 watt amp will not be good on your electrical system. it depends who you get the subs from. if you know the subs were refurbed by kicker then yes, they are good. it's risky buying refurbs through ebay.
You must set your gains properly or kiss your subs good bye. Happened to me running an Orion 2500 they blew after a few mins because I didn't touch the gains. I had to learn the hard way.