Only FRPP dealers can sell FRPP products. The shocks are in the catalog so they should be able to come up with the number easy enough. Otherwise consult a FRPP catalog, it's in there. (I do not have one or I would look for you)
I tried to help you out.......looking through the 2004 catalog right now. Page 174 is all I find .....very confusing.....has a listing for PN M-18125-R58 (Koni) 95 Cobra R rear shock for Mustang Cobra R.......doesn't fit 99-04 Cobra though. Check PN M-18125-G607 rear shock.....there is a pic, but no application description. Nothing for a 2000 Cobra R. Front for the 2000 R is M-18124-R00 (Bilstein). Hope this helps a little.
Whoops.....now on page 130 I find that the PN M-18125-R58 (Koni) 95 Cobra R rear shock can..... 1) be used on 94-02 Mustang...2) except 99-01 Cobra. Everything else is the same. :shrug: