You really need to do more research and make your own decision. There are lots of good threads and debates here about the subjects.
A good twin turbo system will make your car into a ridiculous beast. Fast as hell and borderline not even streetable. Twin turbo will also cost $10000 done properly and be extremely expensive to maintain.
A single turbo is good too but still expensive and mechanically complex (expensive to maintain).
A centrifugal supercharger or 'snail' is the most popular way to boost your car and is also the easiest to install.
One new technology is the remote turbo mounted in the back but to me that is still too mechanically complex...
Do your research and choose the method that is right for you and your goals