Had a bad experience with Adrians Auto Repairs, though quite a few year ago. (might have changed since).
My recommendations:
NT Auto Repairs
John Lovich
(08) 8947 4746
http://www.ntautorepairs.com.au/9 Steele Street, Winnellie, Darwin, NT
Been doing a great job of servicing my Mahindra. -- Has to be one of the cleanest workshops that I have seen -- seems to enjoy working on my vehicle (considering it's a Mahindra

)
Action Automotive
Ed
(08) 8948 4110
297 Bagot Rd Coconut Grove NT 0810
Been serving my sons car, used to use him for my R51 Pathfinder -- Can well recommend.
Both these workshops seem to give a personal touch, are friendly, and complete what has been asked of them in a timely manor.