Hi all, originally posted to ask a question but came across most of the info afterwards. Very sorry, but I leave this thread as a full conversion guide. Veterans are welcome to pick this apart for accuracy (PLEASE DO! ).

Just picked up a '02 C5 and am in the process of prepping for autoX this year for B street. The car came with the soft suspension option (FE1) and while I was planning a shock/front sway bar upgrade, I wasn't sure if I should be looking at upgrading to the Z51 suspension package for the rear sway bar and springs. Class rules do not permit the rear bar or springs to be modified unless it was part of a whole package, meaning I need to do the package conversion completely to be class legal.

Found 2 threads with most of the info except definitive spring rates for FE1/Z51:
https://www.corvetteforum.com/forums...s-97-04-a.html
https://www.corvetteforum.com/forums...00-frc-c5.html

My questions were:

1) Is the rear sway bar stiffer, and does it use the same end links as a FE1 front/rear?
2) Are the springs used across any other models than just Z51s? i.e. could I source them from other variants (Z, later years, etc)?

Sway bar sizes for 00-04 years:

C5 Base Suspension: 23 mm-front / 19.1 mm-rear / 3.81mm/2.0mm thickness
C5 Z51 (00-04): 28.6 mm-front / 23.6 mm-rear / 4.15mm/3mm thickness

GM OEM Z06/Z51 Rear Swaybar: 10424743
GM OEM Z06/Z51 Rear swaybar bushings 10431951 (2 needed)
Z51 Front spring: 22178729 (note: same as Z06)
Z51 Rear spring: 22179020 (FE1 p/n is 22179019, therefore different)

Notes:
• Z06/Z51 shared the rear sway bar/bushing and front spring Part #s, and yes they are stiffer than FE1.
• Z51 also has a different rear spring...??
• Seems from part numbers only the Z06 got aluminum rear end links??

• This link tells how to swap the swaybar:
http://www.ls1howto.com/index.php?article=16
• How to swap the springs:
http://www.ls1howto.com/index.php?article=20

Side note: converting one part means doing it all, so I suppose the changes to the springs would be necessary regardless if I do the rear sway. Seems the FE1 has firmer springs but softer sways and Z51 vice versa from what I gather? Research on spring rates was a bit spotty.

3) I understood there to be a p/s cooler as part of the package, was there anything else? My car is a 6 speed MM6/MN6 with the 3.42 rear end (GU6), which I believe the FRCs came with that had Z51

• Based on RPO codes, the Z51 option did include a p/s cooler. Seems also there may have been a specific diff option based on FRC RPO codes (MM6/MN6, GU6)

All comments and critique are welcome! Would like to ensure an accurate post for later users.