There is not fixed rule as thumb for issues really, issues happen when they want to happen stock or remapped. If you do get issues after the remap they are only going to be minor issues, like the dv coils, maf, boost pipes ect..
I had a Mk5 GT dgs in around a 4 weeks back with 145miles on the clock, it made good power on the dyno and pulled very strong and smooth on the road without any issuse, and touch wood the car is still going strong and going like a rocket with out any issues. Infact he is wanting to book in for a milltek full turbo back system and stage 2 260bhp remap.
Nick