Yes, OP said manual. I'd recommend what I use - Castrol Syntrans V-FE 75W-80,
which is sold as Castrol Transmax Manual V 75W-80 on some markets. At least to
me they both seem the same. It's just a tad thicker as the factory fill VW G 052 527.
8 cSt instead of just 6 cSt, pourpoint -60°C, SDS suggests majority PAO. There are
some VOAs available. Like most of the time there are alternatives. Just make sure
it's GL-4 and not too thick.
VAQ/Haldex (for those who don't know - it's the exact same multi-plate clutch unit)
- just some time ago I would have said just stay with OE VW/Haldex fluid. Today I'd
suggest this though, as on paper at least it looks superior and it's also far cheaper:
https://www.ravenol.de/en/oilltest/oil-test-analyse-awd-h-fluid/
Volkswagen recommends 36 months regardless of miles, which is highly insufficient
when running the car at autocross and on hill climbs where the diff is used hard to
a large extend. I use to change VAQ/Haldex fluid every two years/15kmls and would
highly recommend the OP should swap it every year/10k at the very least.