Like Andre Bottle said, this is a guy that developed upgrades for some classic Rubi-Ka weapons. And since Andre Bottle only sells basic upgrades, you'll have to perform some tasks for engineer Bridges in order to get advanced versions of upgrades. Unfortunatly this also means you'll need to gain his trust first (first two missions can only be pulled once, next two for upgrades can be done over and over again).
For your first task, Engineer Heath Bridges wants you to collect 3 different robot parts. Each one drops from specific mobs found just in 1 location. The list include Processor Chip from Hatchet/Pierce Class Slayerdroids, Tail Flip from Problets and Flourocarbon Cooling Liquid from Hunter Droids. Droprate of each item is about 10% and lower levels are advise to do whole quest line in team.
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Once you return to engineer with all 3 parts, he wants you to test his guardbot. In order to activate it, you're issued with A-9000 Guardbot Controller and map waypoint to it's location.
When there, just open dialog with it and place Controller in it. Of course you should really prepare first, since like Bridges told you, robot will instqantly attack you upon activation. After you overpower it, report your findings to engineer (don't worry about your replies, this is a test, so critism is feedback as well).
Now we come to the parts where instead of credits, you'll get upgrade of your choice for reward (next two missions can be repeated). In order to to fund his research, engineer Bridges also has ouple of facillities. Unfortunatly the one in Stret West Bank got infected by Buckethead Alloy Grafters. So he asks you to travel there and get rid of them (just kill 6 of them). Upon your return, you'll be able to choose 1 of basic weapon upgrade.
After this, he sends you over to Mort, to his other site, to get rid of 6 Buzzsaw Metal Grinders and he'll reward you with one of advanced weapon upgrades of your choosing.
After you complete the line, you can return to engineer Heath Bridges anytime you want and pick basic or advanced upgrade quest (or both if you wish so). And reward will be always ql 180 (ql that can comine with ql 200 or lower weapon).