Other NICO friendly vendors are Stillen and Southwest Autoworks.
Those will give him an idea of what type of products are available to enhance his Maxima. I would also suggest looking at some of the Max's on Car Domain.
Some individual-run sites are
http://www.fastmaxima.com/ and
http://www.ceasarschariot.com/. Both of those guys (NICO members also) are hard-core! Be sure to check out their videos that prove they know what they're talking about.
Hell, just tell your friend to join NICO, and we'll raise him the right way! :ylsuper