I am really surprised to hear that, SEOs usually spam like hell on High PR sites just to increase their PR. But your case is quite different, although your dreams of achieving high PR is unfortunately not going to happen (at least not any sooner) your efforts might get more traffic and even get your website more exposure via Search Engines (provided your website has good quality contents that include important keywords).
Note: Please be notified that it has been almost 2 years since Google has updated PR. And there are rumors that Google might never do that, this is in order to prevent PR from becoming an encouragement factor for Spamming. Google has also notified that PR no longer plays any crucial role and that fairly new websites can rank equally well.!