What 'cha want to know? Production of 996 Turbo's began in '01. They're the best value out there right now for a Porsche Turbo. Older, 993 models are extremely expensive still...I can point several '97's at close to $70K asking prices right now.
Clean, average miles '01-02 turbo's can be found for $40ish. Might be able to squeek an '03 into that budget if it's got some miles. For extremely nice, low mile cars with a few tastey mods you're closer to $45-50. Highly moded ones depend on how much $$$ was spent on them.
As I stated previously, great power, suprisinly comfy and roomy (though you better find one to try out 'cause you're a big dude), civil yet powerful, great handling, AWD, etc. They hvae back seats for insurance resons only. They're basically useless.
Turbo's and GT3's get the coveted GT1 engine block. it's nearly indestructible and the same block and basic components that Porsche Motorsport uses in their factory race cars. (Turbo's obviously get slightly different rods and a lower compression) Little known fact is that other than the induction and engine management the motor in the GT3 street car is exactly the same motor as Porsche cup cars come with. Every single component inside the engine is exactly the same.
With a chip and exhaust turbo's will make a reliable 500-ish hp (crank). With turbo, intercooler upgrades they'll make a reliable 550-600hp. If you go crazy the sky is the limit.
Rennlist forums are the best Porsche resource on the internet. 6-speed however is a better resource for finding quality cars for sale. If you'd like to know more I have a couple of great local porsche resources that I can put you in touch with that not only can get you a drive in one but can find you one if you're serious about buying too.
Andy