Suspension Upgrade for LS Swapped Brougham
 

My '90 Brougham has a fresh LS swap (Gen III 5.3 and 4L60e). The factory suspension isn't adequate for the improved power, quickness, and speed. Anyone have experience with upgrading their suspension or have any suggestions? For example, is the '94-'96 Impala SS or 90's Chevy police interceptor suspension a bolt-on option, or is the '93-'96 RWD Fleetwood suspension stiffer (they have the same frame as the 80-92 RWD, right?) Thanks in advance for any input.