I have found a few more things about the M30 online through reviews from the usual car mags, caranddriver.com, motortrend.com, edmunds.com, various used car sites, and forums for some Nissan related sites, like this one and freshalloy.com, maxima.org, and g35driver.com.
However, if you really want help modding your M30, you may find more people with more experience from the Japanese. The M30 is a luxo American version of the 1986-1991 Nissan Leopard model F31 in Japan. I have done a search on Google before and came across a Japanese group who all modded their F31. Just email them and hope they are fluent enough in English. . . or that they can understand your Japanese.
Try the links or conference page here:
http://www.dcn.ne.jp/~square/pine/leopard/