I understand that the Nikkor 35mm f/1.4 is a fx lens. Will there be any compromise in quality or anything if I used 1.4 instead of 1.8 on a dx camera? Cost is not an issue.
You should ask Nikon and Sigma about that...
It's not the only case. You said that cost is not an issue for you, so you're free to choose whatever you're more pleased with.
Is this true? Does 1.8 beats the 1.4 in terms of minimising distortion?
'For DX you already have the 35 mm f/1.8 G DX which gives sharp images. For FX, this Nikkor can be given a miss. No doubt it has amazing optical quality but the caveats like distortion and chromatic aberration are deal breakers after the price paid. This situation is not helped by the fact that it’s all plastic which reduces the lifespan of this glass by a great degree.'