Get a new Z!!!!!!! Dont go used lol the Z 's from 03 and 04 had tranny problems and tire feathering issues. Make sure you get an extended warranty with the car if possible, just my .2
I got a used one and didnt know it had a bit of a tranny issue till
4 months later so I said F it and jumped into an 06, now I gota worry bout Oil consumption problems haha

 

Have you considered a new IS350? Fantastic new engine according to Ward's.