Mevi

Where can i find a MEVi?
How much do they cost?
How much difference do they make?

you can find them here. http://www.courtesyparts.com/scroll down on the right side click on maxima and your year.
make quite a big differance on top end horsepower

you'll need an ECU with an extended redline to get the full effects. The MEVI from courtesy doesn't have all the parts you need. You'll still need the RPM switch and some various other parts.

I would save enough money to get a JWT ECU with a 7200 RPM redline and the MEVI together. They are a wicked combination and are the best power gainers behind forced induction or Nitrous oxide.