If you know there are allowances then why ask? I'm just confused because to start with you asked if there were any taxes. Goods originating in another country, especially with intent to sell, are going to be subject to tax. Even though it may seem small scale you're essentially assuming the role of 'importer' at that point.
Any tips I've seen given by people regarding this type of question involve the person travelling not being checked or removing packaging and packing 'discretely' in luggage. If you have to 'discretely' pack items to avoid detection it amounts to smuggling and is basically an attempt to circumvent the duties/taxes in place on incoming goods.
That's sort of like asking 'can I speed on the roadways without getting in trouble?' and getting an answer of 'so long as you don't get caught'. It's still breaking the law.
Common sense would say if you're that concerned and considering so many alternatives to avoid making proper declarations or payment, you sort of already know what you're attempting to do isn't legit.
I'm all for folks asking about resources or information on what sort of duties or taxes apply to them, how much they are etc. in order to be prepared. However asking how to circumvent such things isn't appropriate and shouldn't be asked on the forums.
http://www.immihelp.com/travel-to-india/baggage-allowance-rules/used-personal-effects.html
If it was a single graphics card intended for personal use or a gift, even if questioned by a customs agent their determination may be much different than if they ask you to open a piece of luggage and you have 10-20 gpu's loaded up in there. That's no longer 'personal use' and with a large number of items they may view all as imports subject to taxes/fees.