I have had the same problem. Today, I decided to price a new "weatherstrip". It is $97 at Park place for a 97 LS. My leak has been occurring in just one corner near the back glass. So I took off the entire gasket and noticed that along that section (which I then marked), the gasket seal was significantly more pliable (flattened out) than the other remaining sections. The entire gasket is very much the same across the entire run but has many contour bends to fit the trunk. Upon closer scrutiny, the gasket did not appear to be molded in that shape. So, I stuck the gasket in very hot soapy water and cleaned it. I next cleaned the trunk gutter and the trunk lip the gasket was attached to. All were very dirty. After cleaning the gasket, I left it out in the sun to heat up a bit. All the contours were easily straightened out and the gasket became uniform throughout. There is some metal striping that runs inside the gasket for reinforcement and allows it to "clasp" to the trunk lip. In some places the gasket gap was a bit wider than normal so I cinched or clamped by hand back in to standard shape. Lastly, I re-installed the gasket but this time I put the marked (leaky section) on the bottom of the trunk lip near the tail-lights instead of back by the back glass. Several minutes of H20 hose testing ensued with successful results.