Audi TT 2003 3.2 v6 dsg tick over very lumpy and mis firing my mechanic has flushed the engine reckons hasn't had a oil change in ages he says it could have been affecting the variable timing valve ?

SOURCE: Engine has miss-fire

First check spark plugs/wires/distributor cap (tune up). Also would be good idea to use fuel injector cleane and change fuel filter and O2 sensor.
Hope that helps
Good Luck

SOURCE: hi i have a audi tt 3.2 dsg

The problem with your car is that the oil drains back down into the oil pan after sitting. I have this problem at my work where we change oil. After each oil change there is no oil in the motor, it is all in the pan so every single car knocks something fierce when we start it up after adding new oil because it takes awhile to get to where it needs to be.

In your case, probably a seal in the oil pump or the pump itself. Once or twice this is no problem, but if it does it every day you are severely wearing out your engine components without oil flow.

SOURCE: how many miles before an oil change on 2003 audi

DON'T TRUST AUDI MANUALS, MY 2003 A4 PLUGGED OILS LINKS ONLY AFTER 5000 MILES. VW STRETCHED THE MILEAGE OUT TO MAKE A PROFIT AND I REALLY RECOMMEND 4000 INTERVALS, NO LONGER -AT A US EAST COATS TEMP RANGE OF FREEZING TO 10 BELOW TO 15 C - 20 C.

AUDI ENDED UP INCREASING OIL LINE SIZES AND ENLARGING THE OIL FILTER BY 50% AND TELLING ME TO USE THE NEW FILTER FROM THEN ON.

SO LESSON LEARNT, EVEN WITH SYNTHETIC, DO NOT GO BEYOND 4,000 OR BAD THINGS WILL HAPPEN -CALLED ENGINE SLUDGING UP

SOURCE: whats the best audi tt to go for

It should help with fuel economy, but then it is a 3.2V6, so not sure if that would be a priority?
I would suggest if possible test driving the manual. Some people just don't get on with D.S.G. It is governed by the computer so thinks it knows better than you, and won't at points let you change gear. Usually if your DRIVING it enthusiastically.
If you've driven D.S.G before and liked it then without a shadow of a doubt go for it.
It is a lot of money for a gear box so do your sums on the fuel savings and resale value.
Hope it helps?