The first time against Mothrakk I used the car with a machine gun, made distance, switched to gunner, shot it until it came close, and repeated. I got killed hard. Then someone told me that when you're alone in a car, you can use the space bar to lock on to targets. Then it's just a matter of driving circles and holding down RMB.
I'm kind of bummed that most of those bosses are so easy to kill, using either a lot of firepower or a trick. Krom, for example, took me zero effort. I was playing alongside another hunter, and I was at the start of the big canyon where he holes up in. I took my fire sniper, took aim at his turret - no idea it was him sitting in it - and blew it up in three shots. (The guy has a completely bitchin' repeater, btw) There's no satisfaction in that! I'd rather fight a boss that kills everyone twice before the one who gets him survives with barely any health left than this. Just like that little Scythid that the bandits worshipped. Bullets had no effect, so I minced it with my machete, and it was done. Come ooooon.
Man, this game sure gets in your head. I complain about the lack of nicer music in here, and then Patricia Tannis radios me to tell me how she thinks music is stupid and a waste of time.
Something fun happened today, too: I was in the Middle of Nowhere, browsing through the Steam usergroup without any active menus in-game, when Mordecai suddenly says "Why, yes, now that you mention it, I DO like to stand around doing NOTHING!" I laughed my head off. What kind of idle messages do the other characters have?