You have the classic symptoms of worn out shock bushings... If the feeling you get when dipping in to a long sweeper, is sort of a 'wallow', or a feeling of not tracking on a controled arch, I'd look at the upper shock bushings.
Easy to check... Look at the upper shock bolt. It should be dead cented in the shock eye... If it seems to be off center, your bushings have worn to an oval shape, and allow for some sloppy travel. There are a few alternatives to replacing with stock... Gary 'Pruior' sells his version through Chet's Rattlebars page, and my buddy Daryl sells his version through his XF6 Customs page. I know the bushings Daryl sells are warrented forever, and I believe Gary's are too.
XF6's Site;
http://www.xf6-custom.com/partpages/bushings.htmlChet's Site;
http://www.rattlebars.com/Merchant2/merchant.mvc?Screen=SFNT&Store_Code=RMDisclaimer...
I have no affiliation with Chet or Gary. I've been a customer of Chets quite a few times, and have been very happy with any product from him.
Daryl (XF6) is a friend of mine. I have purchased and used the bushings he makes, and can attest to their quality. I have purchased other items from him, and have been a happy customer. I get no $$ for endorsing his products, just the satisfaction of knowing I helped a friend.
Black Dog