I've never really bothered tinkering much with the customization system. It used to be the coolest thing ever, to me, but after my bad experiences online with facing custom jump-sniping gladiators in Mechwarrior 4, I came to realize that customization just gives a way for min-maxers to try to break the game before they even come to the table. The customization system turns me off for everything but campaign style play (Granted it's on a case-by-case basis), and I have yet to have ever played any campaigns outside of Mekwars servers.
But as far as the Marauder goes, I'd always been fond of the Marik variant. The use of Large Lasers helps the design to run a bit cooler, the range difference, negligible, and the lack of a minimum range means it doesn't die in those inevitable short-ranged brawls most of my games turn into.