A follow-up - it took about 9 times to get it done - here's how I did it:
At the start aim for the left of the first corner, go diagonal straight for it - there is no slip stream early , brake late and turn wide - trail braking keeps pace up and revs high, use the rumble strips as you approach turn 3, take the Impreza on the inside, then move to the right of the white Legacy, and take the tight line over the rumble strip on the right hand sweep before the Dunlop bridge. The Black Legacy is next, take it on the right, brake late for the hairpin, same as turn one with some trail breaking, 3/4 way through go full throttle, and then the Blitzen is in reach, use the Blitzen's slipstream to the fullest - (that is very important to gain pace and ground on the '53), pass it half way down the straight - smooth and easy (no panick or rush) through the final turn. Take the '53 on the right. That's a 0.317sec margin.
The race comes to you surprisingly after several frustrating times of waiting 56 seconds for the handicap - replay the last one and the next round strategy while waiting!