Looking for less body roll, and improved handling in general and was wondering what can be done to improve steering feel etc. Is there any aftermarket swaybars, steering rack bushings, polyurethene parts for 00+ bonnevilles?

Yes ssei swaybars will help with body roll. Another thing that would help with body roll is polyurethane endlinks.

Granted I have GPs, but what helped make the feel MUCH better in my mind were STBs. Virtually eliminated body roll.

What are STB'*?

STBs are strut tower braces. You can also install the stb off the GXP bonneville

Dont the Bonnies already come with those? Mine has one for the front.

Don't install just the sways from an SSEi on an SE. You will have an imbalanced and unpredicable suspension.

Go with the FULL FE2 package (springs, sways, ELC) or don't. All or nothing.

The 2000+ Bonnevilles do not come with stb unless its a GXP. The best that know of eliminating body roll without swaping to the full FE2 package is to go with energy suspension polyurethane endlinks.

In comparison, those will do next to nothing compared to STB'*. Many 2k owners have switched to the GXP STB, as have many 87-91 owners switched to the 92-99 STB.