Sure, whilst sacrificing massively in the other areas the MBA excels in. The 8GB of memory in the Air is sufficient for most people, and from my experience is definitely not comparable to having 8GB of memory with Windows. I run a lot of stuff side-by-side and rarely experience memory swapping. But if you want 16GB, then get that config at initial purchase. It's a small 'price' to pay for the convenience of godlike battery like and thermal efficiency.Can't you get something with a better gpu and upgradable RAM at 18k?
If you want a powerful GPU, you probably shouldn't be looking at a MacBook. These aren't for gaming or GPU-heavy workflows.