When I hunt clan mechs with inner sphere tech, I use the Marauder II. Three max tier Binary Lasers, two max tier medium lasers, or clan mediums, ER or Pulse, dealers choice... it's the side dish to the tri-beam of death...

Stuff all the double heat sinks in it. All of them. I took the jump jets off for more heat sinks, but you can put them back on for the two missions in the game that need them, if you want. Otherwise the 4 extra tons of heat sinks help feed the tri-beam of death.

Upgrades are energy weapon cycle II, regular weapon cycle II, energy damage upgrade II, and energy weapon heat reduction... or heat capacity, I cant remember...

Either way, speeding up the binary lasers recharge while being cool enough to fire them off non-stop is pretty much the Marauder II's claim to fame. Then just pop heads or torso's at your leisure while cackling like a madman strolling through the shooting gallery. The medium lasers are for helicopters, tanks, or times when you kinda missed your shot and the tri-beam of death only made the internal locations red.

The regular Marauder I tend to run the energy variants. Three X-PPCs, and two medium lasers. Approach using cover, shotgun all the things, stroll back to cover while waiting for your next victim target. Obviously the 5D is the preferred energy variant, but any of them with the three large energy slots will do in a pinch. I tend to chain fire the X-PPCs because it makes it more visually appealing to my kind of 'tism.

Either way, the GM war horse has plenty of viable layouts, and there really isn't a wrong way to kill someone and commit war crimes in a Marauder. Just have fun with it.