Begin your takedown of August Gaunt as all great endeavours begin- by slapping a hologram.
Follow your marker to the Scandals nightclub for a chat with the bouncer.
He'll tip you off (indirectly) about Gaunt's garage. Follow your marker down, enjoying the pretty lights, and noting the crystal hidden away near the entry.
Search the cars for clues. The first one yields an annoyance, the second one yields an ambush.
Waves of helltroopers will boil up out of the elevators, making that an ideal place for your traps and area effects.
They keep coming until the final wave, which includes a commander and a few pods of boombots.
When everyone but you is dead, investigate the last car to reveal a secret door, secured by a lock that only a master programmer can hack (the mission makes you bring just such a specialist along, so no worries there). Past the lock you'll find Gaunt's favorite car.
Follow the markers. You'll start with 60 seconds on the clock, and time bonuses for every gate you pass through. The timing isn't very tight, so don't worry about making the perfect drift on every turn. Finish your joyride with a crash straight into the targeted doors.
Use your locator scan to find clouds of noxious green mist. This is Gaunt's cologne, and following the trial will lead you to his room.
Gaunt's not around but there is a box to loot and a console to hack. The hack will take some time to finish, and you spend the time killing LEGION. They'll appear in two forces- one back on ground level, and one up top with you, consisting mostly of swarmtroopers, and headed by a shocktrooper.
Dispose of the upper level ones first- the ground levels one will keep. When you are ready for them, you can either snipe from the roof or dive down to distribute death face-to-face. Do watch out for the turret on the left hand side.
When all the LEGION goons are dead, the hack completes. The intel guides you to a rave across town- hop in your car and follow the trail to the shipping containers. When the bouncer gives you a hard time, deck him with a melee attack.
Enter the party and let the cutscene play. When you get control again, shoot up the indicated antennae.
At the second one you'll start to encounter resistance- helltroopers and mindcontrolled civvies, There seems to be no ingame penalty for attacking them, but if it would bother you, try to avoid area attacks for the moment. When all three transmitters are down, kill the remaining goons.
Finishing the fight completes the mission.