Exhaust smoke issue

I've noticed lately i have condensation coming from my tailpipe even after 45min drive but only at idle.
The car is VX SS with extractors and standard cats and 2.5inch redback, cars running fine.
If i give it a hard time there's nothing, but if granny it, its there.

I'm thinking could it be exhaust pipe temp is cool due to larger than normal exhaust, or worst case cracked head or gasket, have checked oil and coolant looks ok.

Other thing there's stuff all back pressure coming from exhaust tip compared to other cars the i own.

Only other thing i can check are plugs