let's say the keywords that i am seo my webpages for are "dodge neon" and "neon parts."

lets also say my url is www.dodgeneon.com

lets also say that i have a keyword density on my pages of "dodge neon" and "neon parts" at the normal percentage, 2-5%.

now, my question is, would it be bad or good to create a subdirectory with my main keyword, "dodge neon" in the main doman and sudirector? Or should i use my secondary keyword, "neon parts." instead?

for example, www.dodgeneon.com/dodge-neon/profile.php647
or
www.dodgeneon.com/neon-parts/profile.php647

I am tryign to maximize my seo and am not sure if this trick will harm me or help me.

Any one know?

I don't think it could hurt. I also think that people over estimate the amount of help that keyword rich URLs do.

I also don't think it will hurt but I also think it wont help that much. If you notice the difference I will be amazed.

My thoughts exactly, vangraan!

I'm often asked this question. SE expert Danny Sullivan's opinion is consitent with the opinions here - it won't help much, if at all.

The SE's have advanced enough not to be fooled by tricks like this nowadays. The goal of the SE's to provide relevant results and have engineered their algorithms thus. So focus on building good content, links etc so that you're seen as 'relevant' by the SE's