Bornatubby

hi guys, very interested in turboing my 350z track in the near future.
I'm not completely familiar with it all, but i dont want to spend too much money.
I'm currently looking on Turbo-kits.com (the only turbo kit website i know)
For a 350z Kit.
They have all different kits but some are producing more power and some are more expensive and producing less power? Can someone explain this to me?

Also, are all these "turbokits" bolt straight onto a stock engine? or will i need to do internal work for the car to be safe.
And I'm hearing stories that 350z sound crap turbo'd. Can anyone give me links of how they'sound? All im interested is spending around $10k all up to put a turbo in as i love the feel of it.
Cheers.