I did my 96 and no leaks.
You don't just replace the seal, you pull it out and re-position in place from the top down,
working your way toward the bottom.
By the time you get to the bottom door sill there should be a 2" gap or so, because the orig seal shrunk.
Insert a 2" piece from the JY there and you should be good.
Do this on a good hot day and the seal will seat better on top corners.
Also check for leaks in the gas pedal area, you may have to pull the windshield wiper cover
and seal the inner cowl. The orig sealant dries up and cracks.
http://www.pontiacbonnevilleclub.com/fo ... 17608.html