You got to give something bak!! i pay £20 a year for the nissan 300zx club too and owners forums are ALWAYS worth the money.
For instance i just insured the Isuzu using the 300zx.co.uk affiliated company and used my members discount and saved £85 !!!! thats over 4 times the joining fee!!
As you put in another post, what would people do if the site just closed one day! imagine their garage bills!