I'm purchasing a G20 in decemeber, so I have a couple of quick questions. How much would it cost to put on a turbocharger into this car. And what 1/4 mile does it give after the alteration? Also does anyone have Xenon installed in their G20? I wanted to know how it looks. Also when will they discontinue the G20 and how does it handle?

Mate, you have a lot of questions...
ALL of them have been answered already. Just lok through the forum or use a the search engine.

Don't know about the rest, but handles very well and Xenon looks good and also won't melt your headlight enclosure (at least the ones I got)

Installed Xenons as well. Have had them for about 1 month, going on 2 - no problems yet. They definitely look better than the stock.

Your engine (SR20) has A LOT of aftermarket parts for it. It is really a good engine, and you should get well over 200hp with a turbo and some breathing enhancements (exhause, intake, K&N, and a chip)

the 2002 g20 model is the last. If I were you, I would wait for the 2003 Infiniti G35. The next step up from the G20. I recommend you go check out the details of this car at infiniti.com. They say that the car is "race bred." ;)