Well as long as the oil was changed once every 7500miles (not km) or 7months, they're bulletproof.
Idle is controlled by the ECU. You can play with the idle set screw, but after a few min it's just going to piss the ECU off and it'll raise the idle back to where-ever in hell it wants it to be!


You should be happy with the 3vz-fe 3.0L v6. It's very similar to the Nissan 3.0L found in the Maxima's. It's argueably a stronger(physically) motor, just without any aftermarket support.

Doesn't matter, the only aftermarket parts you need to make N/A power and can't actually get are cams.
Simple work to the stock intake, new exhaust (y-pipe and back), ported and polished heads, and good ECU tuning should be maxing the stock injectors out badly. At which point you can get a new FPR and do a 190lph walbro swap for possibly a little more. (240-255hp, all depending)
Then you can buy a new clutch/built your Auto transmission and get ready for a turbo!