i run a full A-rated viper, with 2 class 1 beams and 2xMC's class 2, KWS,FSD interception, Discovery scanner,Chaff.....the trick is setting your priorities in the module section properly, simplest way to set it is anything you want for combat goes on 1 or 2, everything else goes 3+ i.e shields, life support,thrusters on 1, weapons (incl KWS) on 2, chaff on 2, things like the FSD,FSD interceptor,discovery scanner hell even the cargo hatch all go on 3+
best thing you get can for a viper is A-rated power plant, thrusters and power regulatator (think thats the name) their the top 3 most important to get